Organic compound, light-emitting element, light-emitting device, electronic device, and lighting device

ABSTRACT

In an organic compound, two groups each including a benzonaphthofuranylamine skeleton are bonded to a central skeleton including a fluorene skeleton. The organic compound emits favorable blue light. Furthermore, the organic compound has a high hole-transport property.

BACKGROUND OF THE INVENTION

1. Field of the Invention

One embodiment of the present invention relates to an organic compound,and a light-emitting element, a display module, a lighting module, adisplay device, a light-emitting device, an electronic device, and alighting device each including the organic compound. Note that oneembodiment of the present invention is not limited to the abovetechnical field. The technical field of one embodiment of the inventiondisclosed in this specification and the like relates to an object, amethod, or a manufacturing method. In addition, one embodiment of thepresent invention relates to a process, a machine, manufacture, or acomposition of matter. Specifically, examples of the technical field ofone embodiment of the present invention disclosed in this specificationinclude a semiconductor device, a display device, a liquid crystaldisplay device, a light-emitting device, a lighting device, a powerstorage device, a memory device, a method for driving any of them, and amethod for manufacturing any of them.

2. Description of the Related Art

As next generation lighting devices or display devices, display devicesusing light-emitting elements (organic EL elements) in which organiccompounds or organometallic complexes are used as light-emittingsubstances have been developed and reported because of their potentialfor thinness, lightness, high-speed response to input signals, low powerconsumption, and the like.

In an organic EL element, voltage application between electrodes,between which a light-emitting layer is interposed, causes recombinationof electrons and holes injected from the electrodes, which brings alight-emitting substance into an excited state, and the return from theexcited state to the ground state is accompanied by light emission.Since the spectrum of light emitted from a light-emitting substancedepends on the light-emitting substance, use of different types oflight-emitting substances makes it possible to obtain light-emittingelements which exhibit various colors.

Displays or lighting devices including organic EL elements can besuitably used for a variety of electronic devices as described above,and light emission mechanism, an element structure, and the like thereofare selected in accordance with applications or characteristicsrequired. In the case where light emission is desired to be obtainedwith high efficiency, an element emitting phosphorescence may be used,and in the case where reliability has priority, fluorescence may beused. In different light emission mechanism, different elementstructures and different materials are used, and the performance maydepend on the positional relation of a level of an orbital or anexcitation level. Therefore, the number of variations of an organiccompound is preferably as large as possible.

In particular, the demand for a carrier-transport material with hightriplet excitation level that can be used as a host material or atransport material in a phosphorescent light-emitting element and a bluefluorescent material has been increased.

Patent Document 1 discloses an organic compound that emits excellentblue fluorescence.

REFERENCE Patent Document

[Patent Document 1] Japanese Published Patent Application No. 2005-42636

SUMMARY OF THE INVENTION

An object of one embodiment of the present invention is to provide anovel organic compound. Another object of one embodiment of the presentinvention is to provide an organic compound that can emit fluorescence.Another object of one embodiment of the present invention is to providean organic compound that can emit blue fluorescence. Another object ofone embodiment of the present invention is to provide an organiccompound that can emit blue fluorescence with favorable chromaticity.Another object of one embodiment of the present invention is to providean organic compound having a high hole-transport property. Anotherobject of one embodiment of the present invention is to provide anorganic compound having high triplet excitation level. Another object ofone embodiment of the present invention is to provide an organiccompound having a high triplet excitation level and a highhole-transport property.

Another object of one embodiment of the present invention is to providean inexpensive organic compound that can emit blue fluorescence. Anotherobject of one embodiment of the present invention is to provide aninexpensive hole-transport material. Another object of one embodiment ofthe present invention is to provide an inexpensive hole-transportmaterial having a high triplet excitation level.

Another object of one embodiment of the present invention is to providea novel light-emitting element. Another object of one embodiment of thepresent invention is to provide a light-emitting element with highemission efficiency. Another object of one embodiment of the presentinvention is to provide a display module, a lighting module, alight-emitting device, a display device, an electronic device, and alighting device each having low power consumption.

It is only necessary that at least one of the above-described objects beachieved in one embodiment of the present invention. Note that thedescriptions of these objects do not disturb the existence of otherobjects. One embodiment of the present invention does not necessarilyhave all the above objects. Other objects will be apparent from and canbe derived from the description of the specification, the drawings, theclaims, and the like.

One embodiment of the present invention is an organic compoundrepresented by the following general formula (G1).A¹-B-A²  (G1)

Note that in the general formula (G1), A¹ and A² separately represent agroup including a benzonaphthofuranylamine skeleton, and B represents agroup including a fluorene skeleton.

Another embodiment of the present invention is an organic compoundrepresented by any one of the following general formulae (B-1) to(B-10).

Note that in the general formulae (B-1) to (B-10), R¹ to R¹⁰, R³⁰ toR³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms.

Note that at least two of R³ to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³,R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ in each of the general formulae(B-1) to (B-10) are groups selected from the general formulae (A-1) to(A-8). Note that the bonding positions where the groups represented bythe general formulae (A-1) to (A-8) are bonded to the organic compoundsrepresented by the general formulae (B-1) to (B-10) are represented by ain the general formulae (A-1) to (A-8).

Note that in the general formulae (A-1) to (A-8), R¹¹ to R¹⁸, R²⁰ toR²⁷, R⁶⁰ to R⁶⁷, and R¹⁰⁰ to R¹¹⁵ separately represent any one ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbongroup having 6 to 13 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, a cyano group, halogen, and asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms.R¹⁹ represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by any one of the following general formulae (B-1) to(B-10).

Note that in the general formulae (B-1) to (B-10), R¹ to R¹⁰, R³⁰ toR³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms.

Note that at least two of R³ to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³,R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ in each of the general formulae(B-1) to (B-10) are groups each represented by the following generalformula (A-3). The general formula (A-3) is bonded to any of the generalformulae (B-1) to (B-10) at a position represented by a.

In the general formula (A-3), R¹² to R¹⁴, R¹⁷, R¹⁸, and R⁶⁰ to R⁶³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms. R¹⁹ represents a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by the following general formula (B-1) or (B-4).

Note that in the general formula (B-1) or (B-4), R¹ to R¹⁰ and R⁵⁰ toR⁵³ separately represent any one of hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substitutedor unsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms,a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms,a cyano group, halogen, and a substituted or unsubstituted haloalkylgroup having 1 to 6 carbon atoms.

At least two of R¹ to R¹⁰ and R⁵⁰ to R⁵³ in each of the general formulae(B-1) and (B-4) are groups each represented by the following generalformula (A-3). Note that the general formula (A-3) is bonded to thegeneral formula (B-1) or (B-4) at a position represented by α.

In the general formula (A-3), R¹² to R¹⁴, R¹⁷, R¹⁸ and R⁶⁰ to R⁶³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms. R¹⁹ represents a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by the following general formula (G2).

Note that in the general formula (G2), R¹ to R³, R⁷, R⁸, R¹⁰, R¹² toR¹⁴, R¹⁷, R¹⁸, R⁵⁰ to R⁵³, and R⁶⁰ to R⁶³ separately represent any oneof hydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbongroup having 6 to 13 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, a cyano group, halogen, and asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms.R¹⁹ represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by the following general formula (G3).

Note that in the general formula (G3), R¹ to R³, R⁵ to R⁸, R¹⁰, R¹² toR¹⁴, R¹⁷, R¹⁸, and R⁶⁰ to R⁶³ separately represent any one of hydrogen,a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 6 carbonatoms, a substituted or unsubstituted aromatic hydrocarbon group having6 to 13 carbon atoms, a substituted or unsubstituted alkoxy group having1 to 6 carbon atoms, a cyano group, halogen, and a substituted orunsubstituted haloalkyl group having 1 to 6 carbon atoms. R¹⁹ representsa substituted or unsubstituted aromatic hydrocarbon group having 6 to 13carbon atoms.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹⁹ is a phenyl group.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹ and R² are each a phenylgroup.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹ and R² are each a methylgroup.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹⁸ is a phenyl group.

Another embodiment of the present invention is an organic compoundrepresented by the following structural formula (101).

Another embodiment of the present invention is an organic compoundrepresented by the following structural formula (117).

Another embodiment of the present invention is an organic compoundrepresented by any of the following general formulae (a-1) to (a-8).

Note that in the above general formulae (a-1) to (a-8), R¹¹ to R¹⁸, R²⁰to R²⁷, R⁶⁰ to R⁶⁷, and R¹⁰⁰ to R¹¹⁵ separately represent any one ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbongroup having 6 to 13 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, a cyano group, halogen, and asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms.R¹⁹ represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 13 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by the following general formula (a-3).

Note that in the above general formula (a-3), R¹² to R¹⁴, R¹⁶, R¹⁷, andR⁶⁰ to R⁶⁷ separately represent any one of hydrogen, a substituted orunsubstituted alkyl group having 1 to 6 carbon atoms, a substituted orunsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substitutedor unsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms,a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms,a cyano group, halogen, and a substituted or unsubstituted haloalkylgroup having 1 to 6 carbon atoms. R¹⁹ represents a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹⁹ is a phenyl group.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹⁸ is a phenyl group.

Another embodiment of the present invention is any of theabove-described organic compounds in which R¹² to R¹⁷, R²⁰ to R²⁷, R⁶⁰to R⁶⁷, and R¹⁰⁰ to R¹¹⁵ are hydrogen.

Another embodiment of the present invention is an organic compoundrepresented by the following structural formula (514).

Another embodiment of the present invention is a light-emitting elementincluding a first electrode, a second electrode, and an organic compoundlayer positioned between the first electrode and the second electrode.The organic compound layer includes any of the above-described organiccompounds.

Another embodiment of the present invention is a light-emitting elementincluding a first electrode, a second electrode, and an organic compoundlayer positioned between the first electrode and the second electrode.The organic compound layer includes a light-emitting layer. Thelight-emitting layer includes any of the above-described organiccompounds.

Another embodiment of the present invention is a light-emitting elementincluding a first electrode, a second electrode, and an organic compoundlayer positioned between the first electrode and the second electrode.The organic compound layer includes a hole-transport layer. Thehole-transport layer includes any of the above-described organiccompounds.

Another embodiment of the present invention is a light-emitting deviceincluding the light-emitting element with any of the above structuresand a transistor or a substrate.

Another embodiment of the present invention is an electronic deviceincluding the above light-emitting device, and a sensor, an operationbutton, a speaker, or a microphone.

Another embodiment of the present invention is a lighting deviceincluding the above light-emitting device and a housing.

Note that the light-emitting device in this specification includes animage display device using a light-emitting element. The light-emittingdevice may be included in a module in which a light-emitting element isprovided with a connector such as an anisotropic conductive film or atape carrier package (TCP), a module in which a printed wiring board isprovided at the end of a TCP, and a module in which an integratedcircuit (IC) is directly mounted on a light-emitting element by a chipon glass (COG) method. The light-emitting device may be included inlighting equipment.

According to one embodiment of the present invention, a novel organiccompound can be provided. An organic compound that can emit bluefluorescence can be provided. An organic compound that can emitfavorable blue fluorescence can be provided. An organic compound havinga high hole-transport property can be provided. An organic compoundhaving high triplet excitation level can be provided. An organiccompound having a high triplet excitation level and a highhole-transport property can be provided.

According to another embodiment of the present invention, an inexpensiveorganic compound that can emit blue fluorescence can be provided.According to another embodiment of the present invention, an inexpensivehole-transport material can be provided. According to another embodimentof the present invention, an inexpensive hole-transport material havinga high triplet excitation level can be provided.

According to another embodiment of the present invention, a novellight-emitting element can be provided. According to another embodimentof the present invention, a display module, a lighting module, alight-emitting device, a display device, an electronic device, and alighting device each having low power consumption can be provided.

It is only necessary that at least one of the above effects be achievedin one embodiment of the present invention. Note that the description ofthese effects does not disturb the existence of other effects. Oneembodiment of the present invention does not necessarily achieve all theeffects listed above. Other effects will be apparent from and can bederived from the description of the specification, the drawings, theclaims, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1C are conceptual diagrams of light-emitting elements.

FIGS. 2A and 2B are conceptual diagrams of an active matrixlight-emitting device.

FIGS. 3A and 3B are conceptual diagrams of an active matrixlight-emitting device.

FIG. 4 is a conceptual diagram of an active matrix light-emittingdevice.

FIGS. 5A and 5B are conceptual diagrams of a passive matrixlight-emitting device.

FIGS. 6A and 6B illustrate a lighting device.

FIGS. 7A to 7D illustrate electronic devices.

FIG. 8 illustrates a light source device.

FIG. 9 illustrates a lighting device.

FIG. 10 illustrates a lighting device.

FIG. 11 illustrates in-vehicle display devices and lighting devices.

FIGS. 12A to 12C illustrate an electronic device.

FIGS. 13A to 13C illustrate an electronic device.

FIGS. 14A and 14B show a ¹H NMR spectrum of(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine.

FIGS. 15A and 15B show a ¹H NMR spectrum of(9,9-dimethyl-9H-fluorene-2,7-diyl)bis(N,6-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine(abbreviation: BnfA2F).

FIGS. 16A and 16B show a ¹H NMR spectrum ofN,N′-(7,7-diphenyl-7H-benzo[c]fluoren-5,9-diyl)bis[(N,6,-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 5,9BnfA2BzFL).

FIGS. 17A and 17B show absorption spectra and emission spectra of atoluene solution and a solid thin film of 5,9BnfA2BzFL.

FIG. 18 shows luminance-current density characteristics of alight-emitting element 1.

FIG. 19 shows current efficiency-luminance characteristics of thelight-emitting element 1.

FIG. 20 shows luminance-voltage characteristics of the light-emittingelement 1.

FIG. 21 shows a current-voltage characteristic of a light-emittingelement 1.

FIG. 22 shows chromaticity coordinate of the light-emitting element 1.

FIG. 23 shows external quantum efficiency-luminance characteristics of alight-emitting element 1.

FIG. 24 shows an emission spectrum of a light-emitting element 1.

FIG. 25 shows luminance-current density characteristics of alight-emitting element 2.

FIG. 26 shows current efficiency-luminance characteristics of thelight-emitting element 2.

FIG. 27 shows luminance-voltage characteristics of the light-emittingelement 2.

FIG. 28 shows current-voltage characteristics of a light-emittingelement 2.

FIG. 29 shows chromaticity coordinate of the light-emitting element 2.

FIG. 30 shows external quantum efficiency-luminance characteristics of alight-emitting element 2.

FIG. 31 shows an emission spectrum of a light-emitting element 2.

FIG. 32 shows luminance-current density characteristics of alight-emitting element 3 and a light-emitting element 4.

FIG. 33 shows current efficiency-luminance characteristics of thelight-emitting element 3 and the light-emitting element 4.

FIG. 34 shows luminance-voltage characteristics of the light-emittingelement 3 and the light-emitting element 4.

FIG. 35 shows current-voltage characteristic of the light-emittingelement 3 and the light-emitting element 4.

FIG. 36 shows external quantum efficiency-luminance characteristic ofthe light-emitting element 3 and the light-emitting element 4.

FIG. 37 shows chromaticity coordinates of the light-emitting element 3and the light-emitting element 4.

FIG. 38 shows emission spectra of the light-emitting element 3 and thelight-emitting element 4.

FIG. 39 shows time dependence of normalized luminance of thelight-emitting element 3 and the light-emitting element 4.

FIGS. 40A and 40B show a ¹H NMR spectrum of4-naphthyl-4′,4″-diphenyltriphenylamine (abbreviation: BBAβNB).

FIGS. 41A and 41B show a ¹H NMR spectrum of3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation:βNP2PC).

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will be explained below withreference to the drawings. Note that the present invention is notlimited to the following description, and it will be readily appreciatedby those skilled in the art that the mode and details can be changed invarious different ways without departing from the spirit and the scopeof the present invention. Accordingly, the present invention should notbe interpreted as being limited to the content of the embodiment below.

In an organic compound of one embodiment of the present invention, twogroups each including a benzonaphthofuranylamine skeleton are bonded toa central skeleton including a fluorene skeleton. The organic compoundemits favorable blue light whose emission spectrum peak is around 450nm. The half width of a peak of the emission spectrum of the organiccompound is narrow, and thus emission of blue light with high colorpurity can be obtained. Furthermore, the organic compound has a highhole-transport property and thus can be favorably used as ahole-transport material. It is particularly preferable to use theorganic compound for a hole-transport layer in a phosphorescentlight-emitting element because the organic compound has high tripletexcitation level. The organic compounds of embodiments of the presentinvention, which have such characteristics, can be represented by thefollowing general formula (G1).A¹-B-A²  (G1)

In the general formula (G1), A¹ and A² separately represent a groupincluding a benzonaphthofuranylamine skeleton, and B represents a groupincluding a fluorene skeleton.

The organic compounds of embodiments of the present invention, whichhave the above characteristics, can also be represented by the followinggeneral formulae (B-1) to (B-10) in B group below.

Note that at least two of R³ to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³,R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ in each of the general formulae(B-1) to (B-10) in the B group are groups selected from the generalformulae (A-1) to (A-8) in A group below. Note that the groupsrepresented by the general formulae (A-1) to (A-8) are bonded to theorganic compounds represented by the general formulae (B-1) to (B-10) atpositions represented by α.

Note that the groups represented by the general formulae (A-1) to (A-8)in A group are preferably each a group including abenzonaphthofuranylamine skeleton represented by the following generalformula (A-3), in which case a high phosphorescent level can beachieved.

When the groups represented by the general formulae (B-1) to (B-10) in Bgroup are each a group including a skeleton represented by the followinggeneral formula (B-4), emission of blue light with high color purity canbe obtained, and thus the groups represented by the general formulae(B-1) to (B-10) can be favorably used for a fluorescent material.

In an organic compound having such a structure, two of the groups eachincluding a benzonaphthofuranylamine skeleton, which are represented bythe general formulae in A group described above, are preferably bondedto the group including a fluorene skeleton, which is represented by anyof the general formulae in B group described above.

In an organic compound having such a structure, the groups eachincluding a benzonaphthofuranylamine skeleton, which are represented bythe general formulae in A group described above, are preferably bondedto the 5-position and the 9-position of the group including a fluoreneskeleton, which is represented by any of the general formulae in B groupdescribed above, for the sake of easy synthesis. Thus, compounds ofembodiments of the present invention can be obtained at low cost. Thatis, an organic compound represented by the following general formula(G-2) is preferable.

In an organic compound represented by the above general formula (G1),when B is a group including a fluorene skeleton represented by thefollowing general formula (B-1), a high T₁ level is obtained and thereis a small possibility that other triplet excitons are quenched;therefore, the organic compound represented by the above general formula(G1) can be favorably used as a material included in a phosphorescentlight-emitting element. The organic compound of one embodiment of thepresent invention has a high hole-transport property and thus can befavorably used as a material included in a hole-transport layer or ahost material in a light-emitting layer. As described above, the organiccompound in which B in the general formula (G1) is a group including afluorene skeleton represented by the following general formula (B-1) hasa high Ti level and thus can be particularly favorably used as amaterial included in a hole-transport layer or a host material in aphosphorescent light-emitting element.

In an organic compound having such a structure, the groups eachincluding a benzonaphthofuranylamine skeleton, which are represented bythe general formulae in A group described above, are preferably bondedto the 2-position and the 7-position of the group including a fluoreneskeleton, which is represented by any of the general formulae in B groupdescribed above, for the sake of easy synthesis. Thus, compounds ofembodiments of the present invention can be obtained at low cost. Thatis, an organic compound represented by the following general formula(G-3) is preferable.

In any of the organic compounds of embodiments of the present invention,R¹⁹ in the above general formulae is preferably a phenyl group.

In any of the organic compounds of embodiments of the present invention,R¹ and R² in the above general formulae are each preferably a phenylgroup.

In any of the organic compounds of embodiments of the present invention,R¹ and R² in the above general formulae are each preferably a methylgroup.

In any of the organic compounds of embodiments of the present invention,R¹⁸ in the above general formulae is preferably a phenyl group.

Note that in the above general formulae (A-1) to (A-8), R¹¹ to R¹⁸, R²⁰to R²⁷, R⁶⁰ to R⁶⁷, and R¹⁰⁰ to R¹¹⁵ separately represent any one ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbongroup having 6 to 13 carbon atoms, a substituted or unsubstituted alkoxygroup having 1 to 6 carbon atoms, a cyano group, halogen, and asubstituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms.R¹⁹ represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 13 carbon atoms. In the general formulae (B-1) to (B-10), R¹to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, andR⁹⁰ to R⁹³ except for the groups represented by the general formulae inA group described above separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 6 carbonatoms, a substituted or unsubstituted aromatic hydrocarbon group having6 to 13 carbon atoms, a substituted or unsubstituted alkoxy group having1 to 6 carbon atoms, a cyano group, halogen, and a substituted orunsubstituted haloalkyl group having 1 to 6 carbon atoms.

Specific examples of an alkyl group having 1 to 6 carbon atoms include amethyl group, an ethyl group, a propyl group, an isopropyl group, ann-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group,an n-pentyl group, a 1-methylbutyl group, a 2-methylbutyl group, a3-methylbutyl group, a 1-ethylpropyl group, a 1,1-dimethylpropyl group,a 1,2-dimethylpropyl group, a 2,2-dimethylpropyl group, and a branchedor non-branched hexyl group. Examples of halogen include fluorine,chlorine, bromine, and iodine.

Specific examples of a cycloalkyl group having 3 to 6 carbon atomsinclude a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, acyclohexyl group, and the like.

Examples of an aromatic hydrocarbon group having 6 to 13 carbon atomsinclude a phenyl group, a biphenyl group, and a fluorenyl group.

In addition, examples of an alkoxy group having 1 to 6 carbon atomsinclude a straight-chain or branched-chain alkyloxy group such as amethoxy group, an ethoxy group, a propoxy group, an isopropoxy group, abutoxy group, an isobutoxy group, a tert-butoxy group, a pentyloxygroup, and a hexyloxy group, and an alkenyloxy group such as a vinyloxygroup, a propenyloxy group, a butenyloxy group, a pentenyloxy group, anda hexenyloxy group.

The haloalkyl group having 1 to 6 carbon atoms is an alkyl group inwhich at least one hydrogen is replaced with a Group 17 element(fluorine, chlorine, bromine, iodine, or astatine). Examples of thehaloalkyl group having 1 to 6 carbon atoms include an alkyl fluoridegroup, an alkyl chloride group, an alkyl bromide group, and an alkyliodide group. Specific examples thereof include a methyl fluoride group,a methyl chloride group, an ethyl fluoride group, and an ethyl chloridegroup. Note that the number of halogen elements and the kinds thereofmay be one or two or more.

Note that in the case where there is a description on the presence orabsence of a substituent for the groups and the skeletons described inthis specification, handling of an alkyl group is different from that ofthe other groups and skeletons. That is, in the case where thedescription “an alkyl group may have a substituent” is made, thesubstituent corresponds to halogen, an alkoxy group having 1 to 6 carbonatoms, or the like. In the case where the description “a group except analkyl group or a skeleton may have a substituent” is made, thesubstituent corresponds to an alkyl group having 1 to 6 carbon atoms, anaromatic hydrocarbon group having 6 to 10 carbon atoms, halogen, analkoxy group having 1 to 6 carbon atoms, or the like.

The organic compounds of embodiments of the present invention, havingthe above structure, can emit favorable blue light with high colorpurity. Furthermore, the organic compound has a high hole-transportproperty and thus can be favorably used as a hole-transport material ora host material in a light-emitting layer. The organic compounds ofembodiments of the present invention each have a high triplet excitationlevel and thus can be particularly favorably used for a hole-transportlayer in a phosphorescent light-emitting element and a host material.

Some specific examples of the organic compounds of embodiments of thepresent invention with the above structure are shown below.

A method for synthesizing an organic compound which is one embodiment ofthe present invention, described above, and represented by the followinggeneral formula (G1) is described.

A variety of reactions can be applied to the method for synthesizing theorganic compound represented by the general formula (G1). For example,synthesis reactions described below enable the synthesis of the organiccompound represented by the general formula (G1). Note that the methodfor synthesizing the organic compound of one embodiment of the presentinvention represented by the general formula (G1) is not limited to thefollowing synthesis method.

<Method of Synthesizing Organic Compound Represented by General Formula(G1)>

The organic compound which is one embodiment of the present inventionand represented by the general formula (G1) can be synthesized by asynthesis scheme (a-1) or (a-2) shown below. That is, abenzonaphthofuranylamino compound (compound 1) is coupled with acompound including a fluorene skeleton (compound 2), whereby abenzonaphthofuranylamino compound (compound 3) can be obtained.Furthermore, the compound 3 is coupled with a benzonaphthofuranylaminocompound (compound 4), whereby an objective substance (G1) can beobtained. Synthesis schemes (a-1) and (a-2) are shown below.

In the case where A¹ and A² are the same in the synthesis of the organiccompound (G1) of one embodiment of the present invention, as shown inthe following synthesis scheme (b-1), a compound including a fluoreneskeleton is coupled with two equivalents of a benzonaphthofuranylaminocompound (compound 1), whereby an objective substance (G1′) can beobtained in one step. The synthesis scheme (b-1) is shown below.

In the synthesis scheme (a-1), (a-2), or (b-1), A¹ and A² separatelyrepresent a benzonaphthofuranylamino group; B represents a bivalentgroup including a fluorene skeleton; X¹ and X² separately representchlorine, bromine, iodine, or a triflate group; and X³ and X⁴ separatelyrepresent hydrogen, an organotin group, or the like.

In the case where the Buchwald-Hartwig reaction using a palladiumcatalyst is employed in the synthesis scheme (a-1) or (a-2), a palladiumcompound such as bis(dibenzylideneacetone)palladium(0), palladium(II)acetate, [1,1-bis(diphenylphosphino)ferrocene]palladium(II)dichloride,tetrakis(triphenylphosphine)palladium(0), or allylpalladium(II) chloridedimer and a ligand such as tri(tert-butyl)phosphine,tri(n-hexyl)phosphine, tricyclohexylphosphine,di(1-adamantyl)-n-butylphosphine,2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl,tri(ortho-tolyl)phosphine, or(S)-6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diisopropylphosphine) can beused. In the reaction, an organic base such as sodium tert-butoxide, aninorganic base such as potassium carbonate, cesium carbonate, or sodiumcarbonate, or the like can be used. In the reaction, toluene, xylene,benzene, tetrahydrofuran, dioxane, or the like can be used as a solvent.Note that reagents that can be used in the reaction are not limited tothe above reagents. In addition, the reaction is preferably performedunder an inert atmosphere of nitrogen, argon, or the like.

In the case where the Ullmann reaction using copper or a copper compoundis performed in the synthesis scheme (a-1), (a-2), or (b-1), X¹ and X²separately represent chlorine, bromine, or iodine, and X³ representshydrogen. Copper or a copper compound can be used for the reaction. Asexamples of bases that can be used in the reaction, inorganic bases suchas potassium carbonate can be given. As examples of solvents that can beused for the reaction, 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone(DMPU), toluene, xylene, benzene, and the like can be given. In theUllmann reaction, since the objective product can be obtained in ashorter time and in a higher yield when the reaction temperature is 100°C. or higher; therefore, it is preferable to use DMPU or xylene that hasa high boiling temperature. A reaction temperature of 150° C. or more isfurther preferred and accordingly DMPU is more preferably used. Notethat reagents that can be used for the reaction are not limited to theabove reagents. In addition, the reaction is preferably performed underan inert atmosphere of nitrogen, argon, or the like.

The organic compound which is one embodiment of the present inventionand represented by the general formula (G1) can be synthesized by asynthesis scheme (c-1) or (c-2) shown below. That is, a compoundincluding a fluorene skeleton (compound 2) is coupled with arylamine(compound 5) and then coupled with a benzonaphthofuran compound(compound 7), whereby an objective substance (G1″) can be obtained. Thesynthesis schemes (c-1) and (c-2) are shown below.

In the synthesis scheme (c-1) or (c-2), R¹¹⁶ represents an aryl grouphaving 6 to 13 carbon atoms; Bnf¹ represents a benzonaphthofuranylgroup; B represents a bivalent group including a fluorene skeleton; andX¹, X², and X⁵ separately represent chlorine, bromine, iodine, or atriflate group.

In the synthesis scheme (c-1) or (c-2), a Buchwald-Hartwig reactionusing a palladium catalyst can be performed. Note that reagents used inthe reaction are the same as those in the synthesis scheme (a-1), (a-2),or (b-1).

In the case where the Ullmann reaction using copper or a copper compoundis performed in the synthesis scheme (c-1) or (c-2), R¹¹⁶ represents anaryl group having 6 to 13 carbon atoms; Bnf¹ represents abenzonaphthofuranyl group; B represents a bivalent group including afluorene skeleton; and X¹ and X² separately represent chlorine, bromine,or iodine. In the case where the Ullmann reaction using copper or acopper compound is performed in the synthesis scheme (c-1) or (c-2),reagents that can be used are the same as those in the synthesis schemes(a-1) or (a-2) and (b-1).

In a method shown in the synthesis scheme (c-1) or (c-2), a product(compound 6) obtained in the scheme (c-1) is fluorenediamine, and theamine is secondary amine. In the case where one molecule includes twosecondary amine structures, for example, the compound is easily oxidizedand has very high polarity; therefore, there are problems such as greatdifficulty in purification and low yield. In contrast, in a method shownin the scheme (a-1), (a-2), or (b-1), the reaction is performed withoutvia a substance including two secondary amine structures (compound 6) asan intermediate, and thus the problems can be reduced. Accordingly, themethod shown in the scheme (a-1), (a-2), or (b-1) is more preferablethan the method shown in the scheme (c-1) or (c-2).

A synthesis of a benzonaphthofuranylamine compound which is a precursorof the organic compound which is one embodiment of the present inventionand represented by the general formula (G1) is described. A structure ofa benzonaphthofuranylamine compound is shown by the following generalformula (g1).

The structures of A¹ and A² in the general formula (G1) which representsan organic compound of one embodiment of the present invention may bethe same or different and can be represented by a general formula (g1).The organic compound which is one embodiment of the present inventionand represented by the general formula (g1) can be synthesized by thefollowing synthesis scheme (d-1). That is, a benzonaphthofuranylcompound (compound 10) is coupled with arylamine (compound 9), whereby abenzonaphthofuranylamino compound (g1) can be obtained. The synthesisscheme (d-1) is shown below.

In the case where the Buchwald-Hartwig reaction using a palladiumcatalyst is employed in the synthesis scheme (d-1), R¹¹⁷ represents anaryl group having 6 to 13 carbon atoms; Bnf² represents abenzonaphthofuranyl group; and X⁶ represents chlorine, bromine, iodine,or a triflate group. In the case where the Buchwald-Hartwig reactionusing a palladium catalyst is employed in the synthesis scheme (d-1),reagents that can be used are the same as those in the synthesis schemes(a-1), (a-2), or (b-1).

In the case where the Ullmann reaction using copper or a copper compoundis performed in the synthesis scheme (d-1), R¹¹⁷ represents an arylgroup having 6 to 13 carbon atoms; Bnf² represents a benzonaphthofuranylgroup; and X⁶ represents chlorine, bromine, or iodine. In the case wherethe Ullmann reaction using copper or a copper compound is performed inthe synthesis scheme (d-1), reagents that can be used are the same asthose in the synthesis schemes (a-1), (a-2), or (b-1).

The compound (g1) is made to be an organotin reagent represented by thefollowing general formula (g1-1) and can be used for the reactions shownby the synthesis schemes (a-1), (a-2), and (b-1).

In the general formula (g1-1), R¹¹⁷ represents an aryl group having 6 to13 carbon atoms; Bnf² represents a benzonaphthofuranyl group; and X⁷represents an organotin group.

Note that in each of the formulae (G1), (a-1), (a-2), (b-1), (c-1), and(c-2), B represents any one of the following general formulae (B-1) to(B-10). In the above formulae (G1), (a-1), (a-2), and (b-1), A¹ and A²separately represent any one of the following general formulae (A-1) to(A-8) which are each bonded to a mother skeleton of B, X³, and X⁴ at aposition represented by α.

Note that in the above general formulae (B-1) to (B-10), R¹ to R¹⁰, R³⁰to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³ and R⁹⁰ to R⁹³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms.

Note that at least two of R³ to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³,R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ in each of the general formulae(B-1) to (B-10) are groups selected from the general formulae (A-1) to(A-8) in A group below.

In the general formulae (A-1) to (A-8), R¹¹ to R¹⁸, R²⁰ to R²⁷, R⁶⁰ toR⁶⁷, and R¹⁰⁰ to R¹¹⁵, separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted aromatic hydrocarbon group having 6 to 13carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6carbon atoms, a cyano group, halogen, and a substituted or unsubstitutedhaloalkyl group having 1 to 6 carbon atoms. R¹⁹ represents a substitutedor unsubstituted aromatic hydrocarbon group having 3 to 6 carbon atoms.

Through the above-described steps, the organic compound of thisembodiment can be synthesized.

As each of Compound 1 and Compound 4 that are used in the synthesisutilizing the reactions shown by the above formulae (a-1), (a-2), and(b-1), any of organic compounds represented by the following formulae(a-1) to (a-8) can be used.

Note that among the compounds represented by the above formulae (a-1) to(a-8), an organic compound synthesized using the organic compoundrepresented by the following general formulae (a-3) can emit blue lightwith high color purity and thus can be favorably used as a fluorescentmaterial.

As specific examples of Compound 1 and Compound 4 used in the abovesynthesis, the following can be given.

<<Light-Emitting Element>>

Next, an example of a light-emitting element which is one embodiment ofthe present invention is described in detail below with reference toFIG. 1A.

In this embodiment, the light-emitting element includes a pair ofelectrodes (a first electrode 101 and a second electrode 102), and an ELlayer 103 provided between the first electrode 101 and the secondelectrode 102. The following description is made on the assumption thatthe first electrode 101 functions as an anode and the second electrode102 functions as a cathode.

To function as an anode, the first electrode 101 is preferably formedusing any of metals, alloys, conductive compounds having a high workfunction (specifically, a work function of 4.0 eV or more), mixturesthereof, and the like. Specific examples include indium oxide-tin oxide(ITO: indium tin oxide), indium oxide-tin oxide containing silicon orsilicon oxide, indium oxide-zinc oxide, and indium oxide containingtungsten oxide and zinc oxide (IWZO). Films of such conductive metaloxides are usually formed by a sputtering method, but may be formed byapplication of a sol-gel method or the like. In an example of theformation method, indium oxide-zinc oxide is deposited by a sputteringmethod using a target obtained by adding 1 wt % to 20 wt % of zinc oxideto indium oxide. Furthermore, indium oxide containing tungsten oxide andzinc oxide (IWZO) can be formed by a sputtering method using a target inwhich tungsten oxide and zinc oxide are added to indium oxide at 0.5 wt% to 5 wt % and 0.1 wt % to 1 wt %, respectively. Other examples aregold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr),molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd),nitrides of metal materials (e.g., titanium nitride), and the like.Graphene can also be used. Note that when a composite material describedlater is used for a layer which is in contact with the first electrode101 in the EL layer 103, an electrode material can be selectedregardless of its work function. It is preferable that the EL layer 103have a stacked-layer structure and any of the layers of thestacked-layer structure contain the organic compound represented by anyone of the general formulae (G1) to (G6) above.

The stacked-layer structure of the EL layer 103 can be formed bycombining a hole-injection layer, a hole-transport layer, alight-emitting layer, an electron-transport layer, an electron-injectionlayer, a carrier-blocking layer, an intermediate layer, and the like asappropriate. In this embodiment, the EL layer 103 has a structure inwhich a hole-injection layer 111, a hole-transport layer 112, alight-emitting layer 113, an electron-transport layer 114, and anelectron-injection layer 115 are stacked in this order over the firstelectrode 101. Specific examples of the materials forming the layers aregiven below.

The hole-injection layer 111 is a layer that contains a substance with ahigh hole-injection property. Molybdenum oxide, vanadium oxide,ruthenium oxide, tungsten oxide, manganese oxide, or the like can beused. Alternatively, the hole-injection layer 111 can be formed using aphthalocyanine-based compound such as phthalocyanine (abbreviation:H₂Pc) or copper phthalocyanine (abbreviation: CuPc), an aromatic aminecompound such as4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation:DPAB) orN,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD), a high molecular compound such aspoly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid) (PEDOT/PSS),or the like.

Alternatively, a composite material in which a substance having ahole-transport property contains a substance having an acceptor propertycan be used for the hole-injection layer 111. Note that the use of sucha substance having a hole-transport property which contains a substancehaving an acceptor property enables selection of a material used to forman electrode regardless of its work function. In other words, besides amaterial having a high work function, a material having a low workfunction can be used for the first electrode 101. As a substance havingan acceptor property, a compound including an electron-withdrawing group(a halogen group or a cyano group) can be used. Examples of such acompound include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane(abbreviation: F₄-TCNQ),3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, and2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation:HAT-CN). As the organic compound having an acceptor property, a compoundin which an electron-withdrawing group is bonded to a condensed aromaticring including a plurality of heteroatoms such as HAT-CN is particularlypreferred because of its thermal stability. In addition, transitionmetal oxides can be given. Moreover, an oxide of metals belonging toGroups 4 to 8 of the periodic table can be used. Specifically, it ispreferable to use vanadium oxide, niobium oxide, tantalum oxide,chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, andrhenium oxide because of their high electron accepting properties. Inparticular, molybdenum oxide is more preferable because of its stabilityin the atmosphere, low hygroscopic property, and easiness of handling.The organic compound having an acceptor property can extract an electronfrom an adjacent hole-transport layer (or a hole-transport material) byapplication of an electric field.

As the substance with a hole-transport property which is used for thecomposite material, any of a variety of organic compounds such asaromatic amine compounds, carbazole derivatives, aromatic hydrocarbons,and high molecular compounds (e.g., oligomers, dendrimers, or polymers)can be used. Note that the substance with a hole-transport propertywhich is used for the composite material is preferably a substancehaving a hole mobility of 10⁻⁶ cm²/Vs or more. Organic compounds thatcan be used as the substance with a hole-transport property in thecomposite material are specifically given below.

Examples of the aromatic amine compounds that can be used for thecomposite material are N,N′-di(p-tolyl)-N,N′-diphenyl-p-phenylenediamine(abbreviation: DTDPPA),4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation:DPAB),N,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD),1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene(abbreviation: DPA3B), and the like. Specific examples of the carbazolederivatives are3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCAl1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2),3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1), 4,4′-di(N-carbazolyl)biphenyl (abbreviation:CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB),9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA),1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, and thelike. Examples of the aromatic hydrocarbons are2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA),2-tert-butyl-9,10-di(1-naphthyl)anthracene,9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA),2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA),9,10-di(2-naphthyl)anthracene (abbreviation: DNA),9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene(abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene(abbreviation: DMNA),2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene,9,10-bis[2-(1-naphthyl)phenyl]anthracene,2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene,2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9′-bianthryl,10,10′-dipenyl-9,9′-bianthryl,10,10′-bis(2-phenylphenyl)-9,9′-bianthryl,10,10′-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9′-bianthryl, anthracene,tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, andthe like. Besides, pentacene, coronene, or the like can also be used.The aromatic hydrocarbons may have a vinyl skeleton. Examples of thearomatic hydrocarbon having a vinyl skeleton are4,4′-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi),9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA),and the like. Note that any of the organic compounds of embodiments ofthe present invention can also be used.

A high molecular compound such as poly(N-vinylcarbazole) (abbreviation:PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), orpoly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation:poly-TPD) can also be used.

By providing the hole-injection layer, a high hole-injection propertycan be achieved to allow a light-emitting element to be driven at a lowvoltage.

Note that the hole-injection layer may be formed of the above-describedacceptor material alone or of the above-described acceptor material andanother material in combination. In this case, the acceptor materialextracts electrons from the hole-transport layer, so that holes can beinjected into the hole-transport layer. The acceptor material transfersthe extracted electrons to the anode.

The hole-transport layer 112 is a layer that contains a substance with ahole-transport property. Examples of the substance with a hole-transportproperty are aromatic amine compounds such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA),4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-penyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), and the like. The substances mentioned here havehigh hole-transport properties and are mainly ones that have a holemobility of 10⁻⁶ cm²/Vs or more. An organic compound given as an exampleof the substance with a hole-transport property in the compositematerial described above can also be used for the hole-transport layer112. A high molecular compound such as poly(N-vinylcarbazole)(abbreviation: PVK) or poly(4-vinyltriphenylamine) (abbreviation: PVTPA)can also be used. In addition, any of the organic compounds ofembodiments of the present invention can also be favorably used. It isparticularly preferable to use, for a light-emitting element including aphosphorescent substance, the organic compound represented by the abovegeneral formula (G1) in which the group represented by B is afluorene-diyl group where a benzene ring is not condensed, such as afluorene-diyl group, a dimethylflorene-diyl group or adiphenylfluorene-diyl group because of its high singlet excitation leveland its high triplet excitation level. Note that the layer that containsa substance with a hole-transport property is not limited to a singlelayer, and may be a stack of two or more layers including any of theabove substances.

The light-emitting layer 113 may be a layer that emits fluorescence, alayer that emits phosphorescence, or a layer emitting thermallyactivated delayed fluorescence (TADF). Furthermore, the light-emittinglayer 113 may be a single layer or include a plurality of layerscontaining different light-emitting substances. In the case where thelight-emitting layer including a plurality of layers is formed, a layercontaining a phosphorescent substance and a layer containing afluorescent substance may be stacked. In that case, an exciplexdescribed later is preferably utilized for the layer containing thephosphorescent substance.

As the fluorescent substance, any of the following substances can beused, for example. Fluorescent substances other than those given belowcan also be used. Examples of the fluorescent substance are5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation:PAP2BPy), 5,6-bis[4′-(10-penyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine(abbreviation: PAPP2BPy),N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N′-diphenylpyrene-1,6-diamine(abbreviation: 1,6FLPAPrn),N,N′-bis(3-methylphenyl)-N,N′-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine(abbreviation: 1,6mMemFLPAPrn),N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S),4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA),4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine(abbreviation: 2YGAPPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene(abbreviation: TBP),4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPA),N,N″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA),N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: 2PCAPPA),N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPPA),N,N,N′,N′,N″,N″,N′″,N′″-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine(abbreviation: DBC1), coumarin 30,N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine(abbreviation: 2PCABPhA),N-(9,10-dipenyl-2-anthryl)-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPA),N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPABPhA),9,10-bis(1,1′-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine(abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine(abbreviation: DPhAPhA), coumarin 545T, N,N′-diphenylquinacridone(abbreviation: DPQd), rubrene,5,12-bis(1,1′-bipenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT),2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile(abbreviation: DCM1),2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCM2),N,N,N′,N′-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation:p-mPhTD),7,14-diphenyl-N,N,N′,N′-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine(abbreviation: p-mPhAFD),2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTI),2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: DCJTB),2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile(abbreviation: BisDCM),2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-ypethenyl]-4H-pyran-4-ylidene}propanedinitrile(abbreviation: BisDCJ™), and the like. Condensed aromatic diaminecompounds typified by pyrenediamine compounds such as 1,6FLPAPrn and1,6mMemFLPAPrn are preferable because of their high hole-trappingproperties, high emission efficiency, and high reliability. Note thatthe organic compounds of embodiments of the present invention are eachpreferably used as a fluorescent substance. A light-emitting elementincluding any of the organic compounds of embodiments of the presentinvention can emit blue light with favorable chromaticity and have highexternal quantum efficiency.

Examples of a material which can be used as a phosphorescent substancein the light-emitting layer 113 are as follows. The examples includeorganometallic iridium complexes having 4H-triazole skeletons, such astris{2-[5-(2-methylpheny)-4H-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN²]phenyl-κC}iridium(III)(abbreviation: [Ir(mpptz-dmp)₃]),tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato) iridium(III)(abbreviation: [Ir(Mptz)₃]), andtris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(iPrptz-3b)₃]); organometallic iridium complexeshaving 1H-triazole skeletons, such astris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(Mptzl-mp)₃]) andtris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) iridium(III)(abbreviation: [Ir(Prptzl-Me)₃]); organometallic iridium complexeshaving imidazole skeletons, such asfac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III)(abbreviation: [Ir(iPrpmi)₃]) andtris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III)(abbreviation: [Ir(dmpimpt-Me)₃]); and organometallic iridium complexesin which a phenylpyridine derivative having an electron-withdrawinggroup is a ligand, such asbis[2-(4′,6′-difluorophenyl)pyridinato-NC^(2′)]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6),bis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III) picolinate(abbreviation: FIrpic),bis{2-[3′,5′-bis(trifluoromethyl)phenyl]pyridinato-N,C^(2′)}iridium(III)picolinate (abbreviation: [Ir(CF₃ppy)₂(pic)]), andbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate (abbreviation: FIr(acac)). These are compounds emittingblue phosphorescence and have an emission peak at 440 nm to 520 nm.

Other examples include organometallic iridium complexes havingpyrimidine skeletons, such as tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)₃]),tris(4-t-butyl-6-phenylpyrimidinato) iridium(III) (abbreviation:[Ir(tBuppm)₃]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)₂(acac)]),(acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato) iridium(III)(abbreviation: [Ir(tBuppm)₂(acac)]),(acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(nbppm)₂(acac)]),(acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(mpmppm)₂(acac)]), and(acetylacetonato)bis(4,6-diphenylpyrimidinato) iridium(III)(abbreviation: [Ir(dppm)₂(acac)]); organometallic iridium complexeshaving pyrazine skeletons, such as(acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato) iridium(III)(abbreviation: [Ir(mppr-Me)₂(acac)]) and(acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)₂(acac)]); organometalliciridium complexes having pyridine skeletons, such astris(2-phenylpyridinato-N,C^(2′)) iridium(III) (abbreviation:[Ir(ppy)₃]), bis(2-phenylpyridinato-N,C^(2′)) iridium(III)acetylacetonate (abbreviation: [Ir(ppy)₂(acac)]),bis(benzo[h]quinolinato) iridium(III) acetylacetonate (abbreviation:[Ir(bzq)₂(acac)]), tris(benzo[h]quinolinato) iridium(III) (abbreviation:[Ir(bzq)₃]), tris(2-phenylquinolinato-N,C^(2′)) iridium(III)(abbreviation: [Ir(pq)₃]), and bis(2-phenylquinolinato-N,C^(2′))iridium(III) acetylacetonate (abbreviation: [Ir(pq)₂(acac)]); and rareearth metal complexes such astris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation:[Tb(acac)₃(Phen)]). These are mainly compounds emitting greenphosphorescence and have an emission peak at 500 nm to 600 nm. Note thatorganometallic iridium complexes having pyrimidine skeletons havedistinctively high reliability and emission efficiency and thus areespecially preferable.

Other examples include organometallic iridium complexes havingpyrimidine skeletons, such as(diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III)(abbreviation: [Ir(5mdppm)₂(dibm)]),bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)₂(dpm)]), andbis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(dlnpm)₂(dpm)]); organometallic iridiumcomplexes having pyrazine skeletons, such as(acetylacetonato)bis(2,3,5-triphenylpyrazinato) iridium(III)(abbreviation: [Ir(tppr)₂(acac)]),bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato) iridium(III)(abbreviation: [Ir(tppr)₂(dpm)]), and(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviation: [Ir(Fdpq)₂(acac)]); organometallic iridium complexeshaving pyridine skeletons, such as tris(1-phenysloquinolinato-N,C^(2′))iridium(III) (abbreviation: [Ir(piq)₃]) andbis(1-phenylisoquinolinato-N,C^(2′)) iridium(III) acetylacetonate(abbreviation: [Ir(piq)₂(acac)]); platinum complexes such as2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II)(abbreviation: PtOEP); and rare earth metal complexes such astris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III)(abbreviation: [Eu(DBM)₃(Phen)]) andtris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III)(abbreviation: [Eu(TTA)₃(Phen)]). These are compounds emitting redphosphorescence and have an emission peak at 600 nm to 700 nm.Furthermore, organometallic iridium complexes having pyrazine skeletonscan provide red light emission with favorable chromaticity.

As well as the above phosphorescent compounds, a variety ofphosphorescent substances may be selected and used.

Examples of the TADF material include a fullerene, a derivative thereof,an acridine derivative such as proflavine, and eosin. Furthermore, ametal-containing porphyrin, such as a porphyrin containing magnesium(Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), orpalladium (Pd) can be used. Examples of the metal-containing porphyrininclude a protoporphyrin-tin fluoride complex (SnF₂(Proto IX)), amesoporphyrin-tin fluoride complex (SnF₂(Meso IX)), ahematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), a coproporphyrintetramethyl ester-tin fluoride complex (SnF₂(Copro III-4Me)), anoctaethylporphyrin-tin fluoride complex (SnF₂(OEP)), anetioporphyrin-tin fluoride complex (SnF₂(Etio I)), and anoctaethylporphyrin-platinum chloride complex (PtCl₂(OEP)), which areshown in the following structural formulae.

Alternatively, a heterocyclic compound having a π-electron richheteroaromatic ring and a π-electron deficient heteroaromatic ring, suchas2-(bipenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine(abbreviation: PIC-TRZ),9-(4,6-dipenyl-1,3,5-triazin-2-yl)-9′-phenyl-9H,9′H-3,3′-bicarbazole(abbreviation: PCCzTzn),2-{4-[3-(N-penyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine(abbreviation: PCCzPTzn),2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-dipenyl-1,3,5-triazine(abbreviation: PXZ-TRZ), 3-[4-(5-penyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation:PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one(abbreviation: ACRXTN),bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation:DMAC-DPS), or 10-phenyl-10H,10′H-spiro[acridin-9,9′-anthracen]-10′-one(abbreviation: ACRSA) shown in the following structural formulae, can beused as the host material 131 composed of one kind of compound. Theheterocyclic compound is preferable because of having the π-electronrich heteroaromatic ring and the π-electron deficient heteroaromaticring, for which the electron-transport property and the hole-transportproperty are high. Note that a substance in which the π-electron richheteroaromatic ring is directly bonded to the π-electron deficientheteroaromatic ring is particularly preferably used because the donorproperty of the π-electron rich heteroaromatic ring and the acceptorproperty of the π-electron deficient heteroaromatic ring are bothincreased, the energy difference between the S₁ level and the T₁ levelbecomes small, and thus thermally activated delayed fluorescence can beobtained with high efficiency. Note that an aromatic ring to which anelectron-withdrawing group such as a cyano group is bonded may be usedinstead of the π-electron deficient heteroaromatic ring.

As a host material of the light-emitting layer, variouscarrier-transport materials, such as a material with anelectron-transport property or a material with a hole-transportproperty, can be used.

Examples of the material with an electron-transport property are a metalcomplex such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II)(abbreviation: BeBq₂),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq),bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), orbis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ); aheterocyclic compound having a triazole skeleton such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ),1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7),9-[4-(5-penyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation:CO11), 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)(abbreviation: TPBI), or2-[3-(dibenzothiophen-4-yl)phenyl]-1-penyl-1H-benzimidazole(abbreviation: mDBTBIm-II); a heterocyclic compound having a diazineskeleton such as2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:2mDBTPDBq-II),2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II),2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine(abbreviation: 4,6mPnP2Pm), or4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation:4,6mDBTP2Pm-II); and a heterocyclic compound having a pyridine skeletonsuch as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) or 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB).Among the above materials, a heterocyclic compound having a diazineskeleton and a heterocyclic compound having a pyridine skeleton havehigh reliability and are thus preferable. Specifically, a heterocycliccompound having a diazine (pyrimidine or pyrazine) skeleton has a highelectron-transport property to contribute to a reduction in drivevoltage.

Examples of the material having a hole-transport property include acompound having an aromatic amine skeleton, such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-penyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), 4-penyl-3′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: mBPAFLP),4-penyl-4′-(9-penyl-9H-carbazol-3-yl)triphenylamine (abbreviation:PCBAlBP), 4,4′-dipenyl-4″-(9-penyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBilBP),4-(1-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBANB),4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBNBB),9,9-dimethyl-N-phenyl-N-[4-(9-penyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine(abbreviation: PCBAF), orN-phenyl-N-[4-(9-penyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine(abbreviation: PCBASF); a compound having a carbazole skeleton, such as1,3-bis(N-carbazolyl)benzene (abbreviation: mCP),4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), or3,3′-bis(9-penyl-9H-carbazole) (abbreviation: PCCP); a compound having athiophene skeleton such as4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation:DBT3P-II),2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene(abbreviation: DBTFLP-III), or4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene(abbreviation: DBTFLP-IV); and a compound having a furan skeleton, suchas 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation:DBF3P-II) or 4-{3-[3-(9-penyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran(abbreviation: mmDBFFLBi-II). Among the above materials, a compoundhaving an aromatic amine skeleton and a compound having a carbazoleskeleton are preferable because these compounds are highly reliable andhave high hole-transport properties to contribute to a reduction indrive voltage. Hole-transport materials can be selected from a varietyof substances as well as from the hole-transport materials given above.Note that the organic compounds of embodiments of the present inventionare each preferably used as a hole-transport material. In particular, inthe case where a group represented by B is a fluorenediyl group which isnot condensed with a benzene ring, such as a fluorenediyl group, adimethylfluorene diyl group, or a diphenylfluorene diyl group, theorganic compound has a high singlet excited level and a high tripletexcitation level and is favorably used as a host material or an assistmaterial in a light-emitting element including a phosphorescentsubstance.

In the case of using a fluorescent substance as a light-emittingsubstance, materials having an anthracene skeleton such as9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation:PCzPA), 3-[4-(1-napthyl)-phenyl]-9H-carbazole ((abbreviation: PCPN),9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA),7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA),6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan(abbreviation: 2mBnfPPA), and9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-bipenyl-4′-yl}-anthracene(abbreviation: FLPPA) are preferably used as host materials. The use ofa substance having an anthracene skeleton as the host material for thefluorescent substance makes it possible to obtain a light-emitting layerwith high emission efficiency and high durability. In particular, CzPA,cgDBCzPA, 2mBnfPPA, and PCzPA are preferable because of their excellentcharacteristics.

Note that the host material may be a mixture of a plurality of kinds ofsubstances, and in the case of using a mixed host material, it ispreferable to mix a material having an electron-transport property witha material having a hole-transport property. By mixing the materialhaving an electron-transport property with the material having ahole-transport property, the transport property of the light-emittinglayer 113 can be easily adjusted and a recombination region can beeasily controlled. The ratio of the content of the material having ahole-transport property to the content of the material having anelectron-transport property may be 1:9 to 9:1.

These mixed host materials may form an exciplex. When a combination ofthese materials is selected so as to form an exciplex that exhibitslight emission whose wavelength overlaps the wavelength of alowest-energy-side absorption band of the fluorescent substance, thephosphorescent substance, or the TADF material, energy is transferredsmoothly and light emission can be obtained efficiently. Such astructure is preferable in that drive voltage can be reduced.

The light-emitting layer 113 having the above-described structure can beformed by co-evaporation by a vacuum evaporation method, or a gravureprinting method, an offset printing method, an inkjet method, a spincoating method, a dip coating method, or the like using a mixedsolution.

The electron-transport layer 114 is a layer including a substance havingan electron-transport property. As a substance having anelectron-transport property, the materials having an electron-transportproperty or having an anthracene skeleton, which are described above asmaterials for the host material, can be used.

Between the electron-transport layer and the light-emitting layer, alayer that controls transport of electron carriers may be provided. Thisis a layer formed by addition of a small amount of a substance having ahigh electron-trapping property to the aforementioned material having ahigh electron-transport property, and the layer is capable of adjustingcarrier balance by retarding transport of electron carriers. Such astructure is very effective in preventing a problem (such as a reductionin element lifetime) caused when electrons pass through thelight-emitting layer.

In addition, the electron-injection layer 115 may be provided in contactwith the second electrode 102 between the electron-transport layer 114and the second electrode 102. For the electron-injection layer 115, analkali metal, an alkaline earth metal, or a compound thereof, such aslithium fluoride (LiF), cesium fluoride (CsF), or calcium fluoride(CaF₂), can be used. For example, a layer that is formed using asubstance having an electron-transport property and contains an alkalimetal, an alkaline earth metal, or a compound thereof can be used. Inaddition, an electride may be used for the electron-injection layer 115.Examples of the electride include a substance in which electrons areadded at high concentration to calcium oxide-aluminum oxide. Note that alayer that is formed using a substance having an electron-transportproperty and contains an alkali metal or an alkaline earth metal ispreferably used as the electron-injection layer 115, in which caseelectron injection from the second electrode 102 is efficientlyperformed.

Instead of the electron-injection layer 115, a charge-generation layer116 may be provided (FIG. 1B). The charge-generation layer 116 refers toa layer capable of injecting holes into a layer in contact with thecathode side of the charge-generation layer 116 and electrons into alayer in contact with the anode side thereof when a potential isapplied. The charge-generation layer 116 includes at least a p-typelayer 117. The p-type layer 117 is preferably formed using any of thecomposite materials given above as examples of materials that can beused for the hole-injection layer 111. The p-type layer 117 may beformed by stacking a film containing the above-described acceptormaterial as a material included in the composite material and a filmcontaining the above-described hole-transport material. When a potentialis applied to the p-type layer 117, electrons are injected into theelectron-transport layer 114 and holes are injected into the secondelectrode 102 serving as a cathode; thus, the light-emitting elementoperates. When a layer containing the organic compound of one embodimentof the present invention exists in the electron-transport layer 114 soas to be in contact with the charge-generation layer 116, a luminancedecrease due to accumulation of driving time of the light-emittingelement can be suppressed, and thus, the light-emitting element can havea long lifetime.

Note that the charge-generation layer 116 preferably includes either anelectron-relay layer 118 or an electron-injection buffer layer 119 orboth in addition to the p-type layer 117.

The electron-relay layer 118 contains at least the substance with anelectron-transport property and has a function of preventing aninteraction between the electron-injection buffer layer 119 and thep-type layer 117 and smoothly transferring electrons. The LUMO level ofthe substance with an electron-transport property contained in theelectron-relay layer 118 is preferably between the LUMO level of anacceptor substance in the p-type layer 117 and the LUMO level of asubstance contained in a layer of the electron-transport layer 114 incontact with the charge-generation layer 116. As a specific value of theenergy level, the LUMO level of the substance with an electron-transportproperty contained in the electron-relay layer 118 is preferably higherthan or equal to −5.0 eV, further preferably higher than or equal to−5.0 eV and lower than or equal to −3.0 eV. Note that as the substancewith an electron-transport property in the electron-relay layer 118, aphthalocyanine-based material or a metal complex having a metal-oxygenbond and an aromatic ligand is preferably used.

A substance having a high electron-injection property can be used forthe electron-injection buffer layer 119. For example, an alkali metal,an alkaline earth metal, a rare earth metal, or a compound thereof(e.g., an alkali metal compound (including an oxide such as lithiumoxide, a halide, and a carbonate such as lithium carbonate or cesiumcarbonate), an alkaline earth metal compound (including an oxide, ahalide, and a carbonate), or a rare earth metal compound (including anoxide, a halide, and a carbonate)) can be used.

In the case where the electron-injection buffer layer 119 contains thesubstance having an electron-transport property and a donor substance,an organic compound such as tetrathianaphthacene (abbreviation: TTN),nickelocene, or decamethylnickelocene can be used as the donorsubstance, as well as an alkali metal, an alkaline earth metal, a rareearth metal, a compound of the above metal (e.g., an alkali metalcompound (including an oxide such as lithium oxide, a halide, and acarbonate such as lithium carbonate or cesium carbonate), an alkalineearth metal compound (including an oxide, a halide, and a carbonate),and a rare earth metal compound (including an oxide, a halide, and acarbonate)). Note that as the substance having an electron-transportproperty, a material similar to the above-described material used forthe electron-transport layer 114 can be used. Furthermore, the organiccompound of the present invention can be used.

For the second electrode 102, any of metals, alloys, electricallyconductive compounds, and mixtures thereof which have a low workfunction (specifically, a work function of 3.8 eV or less) or the likecan be used. Specific examples of such a cathode material are elementsbelonging to Groups 1 and 2 of the periodic table, such as alkali metals(e.g., lithium (Li) and cesium (Cs)), magnesium (Mg), calcium (Ca), andstrontium (Sr), alloys thereof (e.g., MgAg and AlLi), rare earth metalssuch as europium (Eu) and ytterbium (Yb), alloys thereof, and the like.However, when the electron-injection layer is provided between thesecond electrode 102 and the electron-transport layer, for the secondelectrode 102, any of a variety of conductive materials such as Al, Ag,ITO, or indium oxide-tin oxide containing silicon or silicon oxide canbe used regardless of the work function. Films of these conductivematerials can be formed by a dry method such as a vacuum evaporationmethod or a sputtering method, an inkjet method, a spin coating method,or the like. In addition, the films of these conductive materials may beformed by a wet method using a sol-gel method, or by a wet method usingpaste of a metal material.

Any of a variety of methods can be used to form the EL layer 103regardless of whether it is a dry process or a wet process. For example,a vacuum evaporation method, a gravure printing method, an offsetprinting method, a screen printing method, an inkjet method, a spincoating method, or the like may be used.

In addition, the electrode may be formed by a wet method using a sol-gelmethod, or by a wet method using paste of a metal material.Alternatively, the electrode may be formed by a dry method such as asputtering method or a vacuum evaporation method.

Light emission from the light-emitting element is extracted out throughone or both of the first electrode 101 and the second electrode 102.Therefore, one or both of the first electrode 101 and the secondelectrode 102 are formed with a light-transmitting conductive material.

The structure of the layers provided between the first electrode 101 andthe second electrode 102 is not limited to the above-describedstructure. Preferably, a light-emitting region where holes and electronsrecombine is positioned away from the first electrode 101 and the secondelectrode 102 so that quenching due to the proximity of thelight-emitting region and a metal used for electrodes andcarrier-injection layers can be prevented.

Furthermore, in order that transfer of energy from an exciton generatedin the light-emitting layer can be suppressed, preferably, thehole-transport layer and the electron-transport layer which are incontact with the light-emitting layer 113, particularly acarrier-transport layer in contact with a side closer to therecombination region in the light-emitting layer 113, are formed using asubstance having a wider band gap than the light-emitting substance ofthe light-emitting layer or the emission center substance included inthe light-emitting layer.

Next, a mode of a light-emitting element with a structure in which aplurality of light-emitting units are stacked (this type oflight-emitting element is also referred to as a stacked element) isdescribed with reference to FIG. 1C. This light-emitting elementincludes a plurality of light-emitting units between an anode and acathode. One light-emitting unit has the same structure as the EL layer103 illustrated in FIG. 1A. In other words, the light-emitting elementillustrated in FIG. 1A or 1B includes a single light-emitting unit, andthe light-emitting element illustrated in FIG. 1C includes a pluralityof light-emitting units.

In FIG. 1C, a first light-emitting unit 511 and a second light-emittingunit 512 are stacked between a first electrode 501 and a secondelectrode 502, and a charge-generation layer 513 is provided between thefirst light-emitting unit 511 and the second light-emitting unit 512.The first electrode 501 and the second electrode 502 correspond,respectively, to the first electrode 101 and the second electrode 102illustrated in FIG. 1A, and the materials given in the description forFIG. 1A can be used. Furthermore, the first light-emitting unit 511 andthe second light-emitting unit 512 may have the same structure ordifferent structures.

The charge-generation layer 513 has a function of injecting electronsinto one of the light-emitting units and injecting holes into the otherof the light-emitting units when a voltage is applied between the firstelectrode 501 and the second electrode 502. That is, in FIG. 1C, thecharge-generation layer 513 injects electrons into the firstlight-emitting unit 511 and holes into the second light-emitting unit512 when a voltage is applied so that the potential of the firstelectrode becomes higher than the potential of the second electrode.

The charge-generation layer 513 preferably has a structure similar tothe structure of the charge-generation layer 116 described withreference to FIG. 1B. Since the composite material of an organiccompound and a metal oxide is superior in carrier-injection property andcarrier-transport property, low-voltage driving or low-current drivingcan be achieved. Note that when a surface of a light-emitting unit onthe anode side is in contact with the charge-generation layer 513, thecharge-generation layer 513 can also serve as a hole-injection layer ofthe light-emitting unit; thus, a hole-injection layer is not necessarilyformed in the light-emitting unit.

In the case where the electron-injection buffer layer 119 is provided,the electron-injection buffer layer serves as the electron-injectionlayer in the light-emitting unit on the anode side and thelight-emitting unit does not necessarily further need anelectron-injection layer.

Note that when a layer in contact with a surface of thecharge-generation layer 513 on the anode side in a light-emitting unit(typically, the electron-transport layer in the light-emitting unit onthe anode side) contains the organic compound of one embodiment of thepresent invention, a luminance decrease due to accumulation of drivingtime can be suppressed, and thus, the light-emitting element can havehigh reliability.

The light-emitting element having two light-emitting units is describedwith reference to FIG. 1C; however, one embodiment of the presentinvention can be similarly applied to a light-emitting element in whichthree or more light-emitting units are stacked. With a plurality oflight-emitting units partitioned by the charge-generation layer 513between a pair of electrodes as in the light-emitting element accordingto this embodiment, it is possible to provide an element which can emitlight with high luminance with the current density kept low and has along lifetime. A light-emitting device that can be driven at a lowvoltage and has low power consumption can be realized.

Furthermore, when emission colors of the light-emitting units are madedifferent, light emission of a desired color can be obtained from thelight-emitting element as a whole. For example, it is easy to enable alight-emitting element having two light-emitting units to emit whitelight as the whole element when the emission colors of the firstlight-emitting unit are red and green and the emission color of thesecond light-emitting unit is blue.

<<Micro Optical Resonator (Microcavity) Structure>>

A light-emitting element with a microcavity structure is formed with theuse of a reflective electrode and a semi-transmissive andsemi-reflective electrode as the pair of electrodes. The reflectiveelectrode and the semi-transmissive and semi-reflective electrodecorrespond to the first electrode and the second electrode describedabove. The light-emitting element with a microcavity structure includesat least an EL layer between the reflective electrode and thesemi-transmissive and semi-reflective electrode. The EL layer includesat least a light-emitting layer serving as a light-emitting region.

Light emitted from the light-emitting layer included in the EL layer isreflected and resonated by the reflective electrode and thesemi-transmissive and semi-reflective electrode. Note that thereflective electrode has a visible light reflectivity of 40% to 100%,preferably 70% to 100% and a resistivity of 1×10⁻² Qcm or lower. Inaddition, the semi-transmissive and semi-reflective electrode has avisible light reflectivity of 20% to 80%, preferably 40% to 70%, and aresistivity of 1×10⁻² Qcm or lower.

In the light-emitting element, by changing thicknesses of thetransparent conductive film, the composite material, thecarrier-transport material, and the like, the optical path lengthbetween the reflective electrode and the semi-transmissive andsemi-reflective electrode can be changed. Thus, light with a wavelengththat is resonated between the reflective electrode and thesemi-transmissive and semi-reflective electrode can be intensified whilelight with a wavelength that is not resonated therebetween can beattenuated.

Note that light that is emitted from the light-emitting layer andreflected back by the reflective electrode (first reflected light)considerably interferes with light that directly enters thesemi-transmissive and semi-reflective electrode from the light-emittinglayer (first incident light). For this reason, the optical path lengthbetween the reflective electrode and the light-emitting layer ispreferably adjusted to (2n-1)λ/4 (n is a natural number of 1 or largerand λ is a wavelength of color to be amplified). In that case, thephases of the first reflected light and the first incident light can bealigned with each other and the light emitted from the light-emittinglayer can be further amplified.

Note that in the above structure, the EL layer may be formed oflight-emitting layers or may be a single light-emitting layer. Thetandem light-emitting element described above may be combined with theEL layers; for example, a light-emitting element may have a structure inwhich a plurality of EL layers is provided, a charge-generation layer isprovided between the EL layers, and each EL layer is formed oflight-emitting layers or a single light-emitting layer.

<<Light-Emitting Device>>

A light-emitting device of one embodiment of the present invention isdescribed using FIGS. 2A and 2B. Note that FIG. 2A is a top viewillustrating the light-emitting device and FIG. 2B is a cross-sectionalview of FIG. 2A taken along lines A-B and C-D. This light-emittingdevice includes a driver circuit portion (source line driver circuit)601, a pixel portion 602, and a driver circuit portion (gate line drivercircuit) 603, which can control light emission of a light-emittingelement and illustrated with dotted lines. A reference numeral 604denotes a sealing substrate; 605, a sealing material; and 607, a spacesurrounded by the sealing material 605.

Reference numeral 608 denotes a wiring for transmitting signals to beinput to the source line driver circuit 601 and the gate line drivercircuit 603 and receiving signals such as a video signal, a clocksignal, a start signal, and a reset signal from a flexible printedcircuit (FPC) 609 serving as an external input terminal. Although onlythe FPC is illustrated here, a printed wiring board (PWB) may beattached to the FPC. The light-emitting device in the presentspecification includes, in its category, not only the light-emittingdevice itself but also the light-emitting device provided with the FPCor the PWB.

Next, a cross-sectional structure will be described with reference toFIG. 2B. The driver circuit portion and the pixel portion are formedover an element substrate 610; the source line driver circuit 601, whichis a driver circuit portion, and one of the pixels in the pixel portion602 are illustrated here.

As the source line driver circuit 601, a CMOS circuit in which ann-channel FET 623 and a p-channel FET 624 are combined is formed. Inaddition, the driver circuit may be formed with any of a variety ofcircuits such as a CMOS circuit, a PMOS circuit, or an NMOS circuit.Although a driver integrated type in which the driver circuit is formedover the substrate is described in this embodiment, the driver circuitis not necessarily formed over the substrate, and the driver circuit canbe formed outside, not over the substrate.

The pixel portion 602 includes a plurality of pixels including aswitching FET 611, a current controlling FET 612, and a first electrode613 electrically connected to a drain of the current controlling FET612. One embodiment of the present invention is not limited to thestructure. The pixel portion may include three or more FETs and acapacitor in combination.

The kind and crystallinity of a semiconductor used for the FETs is notparticularly limited; an amorphous semiconductor or a crystallinesemiconductor may be used. Examples of the semiconductor used for theFETs include Group 13 semiconductors, Group 14 semiconductors, compoundsemiconductors, oxide semiconductors, and organic semiconductormaterials. Oxide semiconductors are particularly preferable. Examples ofthe oxide semiconductor include an In—Ga oxide and an In-M-Zn oxide (Mis Al, Ga, Y, Zr, La, Ce, or Nd). Note that an oxide semiconductormaterial that has an energy gap of 2 eV or more, preferably 2.5 eV ormore, further preferably 3 eV or more is preferably used, in which casethe off-state current of the transistors can be reduced.

Note that to cover an end portion of the first electrode 613, aninsulator 614 is formed. The insulator 614 can be formed using apositive photosensitive acrylic resin film here.

The insulator 614 is formed to have a curved surface with curvature atits upper or lower end portion in order to obtain favorable coverage.For example, in the case where positive photosensitive acrylic is usedfor a material of the insulator 614, only the upper end portion of theinsulator 614 preferably has a curved surface with a curvature radius(0.2 μm to 3 μm). As the insulator 614, either a negative photosensitiveresin or a positive photosensitive resin can be used.

An EL layer 616 and a second electrode 617 are formed over the firstelectrode 613. The first electrode 613, the EL layer 616, and the secondelectrode 617 correspond, respectively, to the first electrode 101, theEL layer 103, and the second electrode 102 in FIG. 1A or 1B, andcorrespond, respectively, to the first electrode 501, the EL layer 503,and the second electrode 502 in FIG. 1C.

The EL layer 616 preferably includes the organic compound of oneembodiment of the present invention. The organic compound is preferablyused as a light-emitting substance, a hole-transport material, a hostmaterial, or an assist material in a light-emitting layer.

The sealing substrate 604 is attached to the element substrate 610 withthe sealing material 605, so that a light-emitting element 618 isprovided in the space 607 surrounded by the element substrate 610, thesealing substrate 604, and the sealing material 605. The space 607 isfilled with a filler, and may be filled with an inert gas (such asnitrogen or argon) or the sealing material 605. It is preferable thatthe sealing substrate 604 be provided with a recessed portion and adrying agent be provided in the recessed portion, in which casedeterioration due to influence of moisture can be suppressed.

An epoxy-based resin or glass frit is preferably used for the sealingmaterial 605. It is preferable that such a material do not transmitmoisture or oxygen as much as possible. As the element substrate 610 andthe sealing substrate 604, a glass substrate, a quartz substrate, or aplastic substrate formed of fiber reinforced plastic (FRP), polyvinylfluoride (PVF), polyester, or acrylic can be used.

Note that in this specification and the like, a transistor or alight-emitting element can be formed using any of a variety ofsubstrates, for example. The type of a substrate is not limited to acertain type. As the substrate, a semiconductor substrate (e.g., asingle crystal substrate or a silicon substrate), an SOI substrate, aglass substrate, a quartz substrate, a plastic substrate, a metalsubstrate, a stainless steel substrate, a substrate including stainlesssteel foil, a tungsten substrate, a substrate including tungsten foil, aflexible substrate, an attachment film, paper including a fibrousmaterial, a base material film, or the like can be used, for example. Asan example of a glass substrate, a barium borosilicate glass substrate,an aluminoborosilicate glass substrate, a soda lime glass substrate, orthe like can be given. Examples of the flexible substrate, theattachment film, the base material film, and the like are substrates ofplastics typified by polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), and polyether sulfone (PES). Another example is asynthetic resin such as acrylic. Alternatively, polytetrafluoroethylene(PTFE), polypropylene, polyester, polyvinyl fluoride, polyvinylchloride, or the like can be used. Alternatively, polyamide, polyimide,aramid, epoxy, an inorganic vapor deposition film, paper, or the likecan be used. Specifically, the use of semiconductor substrates, singlecrystal substrates, SOI substrates, or the like enables the manufactureof small-sized transistors with a small variation in characteristics,size, shape, or the like and with high current capability. A circuitusing such transistors achieves lower power consumption of the circuitor higher integration of the circuit.

Alternatively, a flexible substrate may be used as the substrate, andthe transistor or the light-emitting element may be provided directly onthe flexible substrate. Still alternatively, a separation layer may beprovided between the substrate and the transistor or the substrate andthe light-emitting element. The separation layer can be used when partor the whole of a semiconductor device formed over the separation layeris separated from the substrate and transferred onto another substrate.In such a case, the transistor can be transferred to a substrate havinglow heat resistance or a flexible substrate. For the separation layer, astack including inorganic films, which are a tungsten film and a siliconoxide film, or an organic resin film of polyimide or the like formedover a substrate can be used, for example.

In other words, a transistor or a light-emitting element may be formedusing one substrate, and then transferred to another substrate. Examplesof a substrate to which a transistor or a light-emitting element istransferred include, in addition to the above-described substrates overwhich transistors can be formed, a paper substrate, a cellophanesubstrate, an aramid film substrate, a polyimide film substrate, a stonesubstrate, a wood substrate, a cloth substrate (including a naturalfiber (e.g., silk, cotton, or hemp), a synthetic fiber (e.g., nylon,polyurethane, or polyester), a regenerated fiber (e.g., acetate, cupra,rayon, or regenerated polyester), or the like), a leather substrate, anda rubber substrate. When such a substrate is used, a transistor withexcellent characteristics or a transistor with low power consumption canbe formed, a device with high durability or high heat resistance can beprovided, or reduction in weight or thickness can be achieved.

FIGS. 3A and 3B each illustrate an example of a light-emitting device inwhich full color display is achieved by formation of a light-emittingelement exhibiting white light emission and with the use of coloringlayers (color filters) and the like. In FIG. 3A, a substrate 1001, abase insulating film 1002, a gate insulating film 1003, gate electrodes1006, 1007, and 1008, a first interlayer insulating film 1020, a secondinterlayer insulating film 1021, a peripheral portion 1042, a pixelportion 1040, a driver circuit portion 1041, first electrodes 1024W,1024R, 1024G, and 1024B of light-emitting elements, a partition 1025, anEL layer 1028, a second electrode 1029 of the light-emitting elements, asealing substrate 1031, a sealing material 1032, and the like areillustrated.

In FIG. 3A, coloring layers (a red coloring layer 1034R, a greencoloring layer 1034G, and a blue coloring layer 1034B) are provided on atransparent base material 1033. A black layer (a black matrix) 1035 maybe additionally provided. The transparent base material 1033 providedwith the coloring layers and the black layer is positioned and fixed tothe substrate 1001. Note that the coloring layers and the black layerare covered with an overcoat layer 1036. In FIG. 3A, light emitted frompart of the light-emitting layer does not pass through the coloringlayers, while light emitted from the other part of the light-emittinglayer passes through the coloring layers. Since light which does notpass through the coloring layers is white and light which passes throughany one of the coloring layers is red, blue, or green, an image can bedisplayed using pixels of the four colors.

Note that a light-emitting element including the organic compound of oneembodiment of the present invention as a light-emitting substance canhave high emission efficiency and low power consumption.

FIG. 3B illustrates an example in which the coloring layers (the redcoloring layer 1034R, the green coloring layer 1034G, and the bluecoloring layer 1034B) are provided between the gate insulating film 1003and the first interlayer insulating film 1020. As in the structure, thecoloring layers may be provided between the substrate 1001 and thesealing substrate 1031.

The above-described light-emitting device is a light-emitting devicehaving a structure in which light is extracted from the substrate 1001side where the FETs are formed (a bottom emission structure), but may bea light-emitting device having a structure in which light is extractedfrom the sealing substrate 1031 side (a top emission structure). FIG. 4is a cross-sectional view of a light-emitting device having a topemission structure. In this case, a substrate which does not transmitlight can be used as the substrate 1001. The process up to the step offorming a connection electrode which connects the FET and the anode ofthe light-emitting element is performed in a manner similar to that ofthe light-emitting device having a bottom emission structure. Then, athird interlayer insulating film 1037 is formed to cover an electrode1022. This insulating film may have a planarization function. The thirdinterlayer insulating film 1037 can be formed using a material similarto that of the second interlayer insulating film, and can alternativelybe formed using any of various materials.

The first electrodes 1024W, 1024R, 1024G, and 1024B of thelight-emitting elements each serve as an anode here, but may serve as acathode. Furthermore, in the case of a light-emitting device having atop emission structure as illustrated in FIG. 4, the first electrodesare preferably reflective electrodes. The EL layer 1028 is formed tohave a structure similar to the structure of the EL layer 103 in FIG. 1Aor 1B or the EL layer 503 in FIG. 1C, with which white light emissioncan be obtained.

In the case of a top emission structure as illustrated in FIG. 4,sealing can be performed with the sealing substrate 1031 on which thecoloring layers (the red coloring layer 1034R, the green coloring layer1034G, and the blue coloring layer 1034B) are provided. The sealingsubstrate 1031 may be provided with the black layer (black matrix) 1035which is positioned between pixels. The coloring layers (the redcoloring layer 1034R, the green coloring layer 1034G, and the bluecoloring layer 1034B) and the black layer may be covered with theovercoat layer. Note that a light-transmitting substrate is used as thesealing substrate 1031.

Although an example in which full color display is performed using fourcolors of red, green, blue, and white is shown here, there is noparticular limitation and full color display using three colors of red,green, and blue or four colors of red, green, blue, and yellow may beperformed.

FIGS. 5A and 5B illustrate a passive matrix light-emitting device whichis one embodiment of the present invention. FIG. 5A is a perspectiveview of the light-emitting device, and FIG. 5B is a cross-sectional viewof FIG. 5A taken along line X-Y. In FIGS. 5A and 5B, an EL layer 955 isprovided between an electrode 952 and an electrode 956 over a substrate951. An end portion of the electrode 952 is covered with an insulatinglayer 953. A partition layer 954 is provided over the insulating layer953. The sidewalls of the partition layer 954 are aslope such that thedistance between both sidewalls is gradually narrowed toward the surfaceof the substrate. In other words, a cross section taken along thedirection of the short side of the partition layer 954 is trapezoidal,and the lower side (a side which is in the same direction as a planedirection of the insulating layer 953 and in contact with the insulatinglayer 953) is shorter than the upper side (a side which is in the samedirection as the plane direction of the insulating layer 953 and not incontact with the insulating layer 953). The partition layer 954 thusprovided can prevent defects in the light-emitting element due to staticelectricity or the like.

Since many minute light-emitting elements arranged in a matrix can eachbe controlled with the FETs formed in the pixel portion, theabove-described light-emitting device can be suitably used as a displaydevice for displaying images.

<<Lighting Device>>

A lighting device which is one embodiment of the present invention isdescribed with reference to FIGS. 6A and 6B. FIG. 6B is a top view ofthe lighting device, and FIG. 6A is a cross-sectional view of FIG. 6Btaken along line e-f.

In the lighting device, a first electrode 401 is formed over a substrate400 which is a support and has a light-transmitting property. The firstelectrode 401 corresponds to the first electrode 101 in FIGS. 1A and 1B.When light is extracted through the first electrode 401 side, the firstelectrode 401 is formed using a material having a light-transmittingproperty.

A pad 412 for applying a voltage to a second electrode 404 is providedover the substrate 400.

An EL layer 403 is formed over the first electrode 401. The EL layer 403corresponds to, for example, the EL layer 103 in FIG. 1A or 1B or the ELlayer 503 in FIG. 1C. Refer to the descriptions for the structure.

The second electrode 404 is formed to cover the EL layer 403. The secondelectrode 404 corresponds to the second electrode 102 in FIG. 1A. Thesecond electrode 404 contains a material having high reflectivity whenlight is extracted through the first electrode 401 side. The secondelectrode 404 is connected to the pad 412, whereby a voltage is applied.

A light-emitting element is formed with the first electrode 401, the ELlayer 403, and the second electrode 404. The light-emitting element isfixed to a sealing substrate 407 with sealing materials 405 and 406 andsealing is performed, whereby the lighting device is completed. It ispossible to use only either the sealing material 405 or the sealingmaterial 406. In addition, the inner sealing material 406 (not shown inFIG. 6B) can be mixed with a desiccant, whereby moisture is adsorbed andthe reliability is increased.

When parts of the pad 412 and the first electrode 401 are extended tothe outside of the sealing materials 405 and 406, the extended parts canserve as external input terminals. An IC chip 420 mounted with aconverter or the like may be provided over the external input terminals.

<<Electronic Device>>

Examples of an electronic device which is one embodiment of the presentinvention are described. Examples of the electronic device aretelevision devices (also referred to as TV or television receivers),monitors for computers and the like, cameras such as digital cameras anddigital video cameras, digital photo frames, mobile phones (alsoreferred to as cell phones or mobile phone devices), portable gamemachines, portable information terminals, audio playback devices, andlarge game machines such as pachinko machines. Specific examples ofthese electronic devices are given below.

FIG. 7A illustrates an example of a television device. In the televisiondevice, a display portion 7103 is incorporated in a housing 7101. Inaddition, here, the housing 7101 is supported by a stand 7105. Imagescan be displayed on the display portion 7103, and in the display portion7103, light-emitting elements are arranged in a matrix.

The television device can be operated with an operation switch of thehousing 7101 or a separate remote controller 7110. With operation keys7109 of the remote controller 7110, channels and volume can becontrolled and images displayed on the display portion 7103 can becontrolled. Furthermore, the remote controller 7110 may be provided witha display portion 7107 for displaying data output from the remotecontroller 7110.

Note that the television device is provided with a receiver, a modem,and the like. With the use of the receiver, general televisionbroadcasting can be received. Moreover, when the television device isconnected to a communication network with or without wires via themodem, one-way (from a sender to a receiver) or two-way (between asender and a receiver or between receivers) information communicationcan be performed.

FIG. 7B1 illustrates a computer, which includes a main body 7201, ahousing 7202, a display portion 7203, a keyboard 7204, an externalconnection port 7205, a pointing device 7206, and the like. Note thatthis computer is manufactured by using light-emitting elements arrangedin a matrix in the display portion 7203. The computer illustrated inFIG. 7B1 may have a structure illustrated in FIG. 7B2. A computerillustrated in FIG. 7B2 is provided with a second display portion 7210instead of the keyboard 7204 and the pointing device 7206. The seconddisplay portion 7210 is a touchscreen, and input can be performed byoperation of display for input on the second display portion 7210 with afinger or a dedicated pen. The second display portion 7210 can alsodisplay images other than the display for input. The display portion7203 may also be a touchscreen. Connecting the two screens with a hingecan prevent troubles; for example, the screens can be prevented frombeing cracked or broken while the computer is being stored or carried.

FIGS. 7C and 7D illustrate an example of a portable informationterminal. The portable information terminal is provided with a displayportion 7402 incorporated in a housing 7401, operation buttons 7403, anexternal connection port 7404, a speaker 7405, a microphone 7406, andthe like. Note that the portable information terminal has the displayportion 7402 including light-emitting elements arranged in a matrix.

Information can be input to the portable information terminalillustrated in FIGS. 7C and 7D by touching the display portion 7402 witha finger or the like. In this case, operations such as making a call andcreating an e-mail can be performed by touching the display portion 7402with a finger or the like.

There are mainly three screen modes of the display portion 7402. Thefirst mode is a display mode mainly for displaying an image. The secondmode is an input mode mainly for inputting information such ascharacters. The third mode is a display-and-input mode in which twomodes of the display mode and the input mode are combined.

For example, in the case of making a call or creating an e-mail, a textinput mode mainly for inputting text is selected for the display portion7402 so that text displayed on a screen can be input. In this case, itis preferable to display a keyboard or number buttons on almost theentire screen of the display portion 7402.

When a detection device including a sensor such as a gyroscope or anacceleration sensor for sensing inclination is provided inside themobile phone, screen display of the display portion 7402 can beautomatically changed by determining the orientation of the mobile phone(whether the mobile phone is placed horizontally or vertically).

The screen modes are switched by touch on the display portion 7402 oroperation with the operation buttons 7403 of the housing 7401. Thescreen modes can be switched depending on the kind of images displayedon the display portion 7402. For example, when a signal of an imagedisplayed on the display portion is a signal of moving image data, thescreen mode is switched to the display mode. When the signal is a signalof text data, the screen mode is switched to the input mode.

Moreover, in the input mode, when input by touching the display portion7402 is not performed for a certain period while a signal detected by anoptical sensor in the display portion 7402 is detected, the screen modemay be controlled so as to be switched from the input mode to thedisplay mode.

The display portion 7402 may function as an image sensor. For example,an image of a palm print, a fingerprint, or the like is taken by thedisplay portion 7402 while in touch with the palm or the finger, wherebypersonal authentication can be performed. Furthermore, by providing abacklight or a sensing light source which emits near-infrared light inthe display portion, an image of a finger vein, a palm vein, or the likecan be taken.

Note that in the above electronic devices, any of the structuresdescribed in this specification can be combined as appropriate.

The display portion preferably includes a light-emitting elementincluding the organic compound of one embodiment of the presentinvention. The light-emitting element can have high emission efficiency.Furthermore, the light-emitting element can be driven at low voltage.Thus, the electronic device including the organic compound of oneembodiment of the present invention can have low power consumption.

FIG. 8 illustrates an example of a liquid crystal display deviceincluding the light-emitting element for a backlight. The liquid crystaldisplay device illustrated in FIG. 8 includes a housing 901, a liquidcrystal layer 902, a backlight unit 903, and a housing 904. The liquidcrystal layer 902 is connected to a driver IC 905. The light-emittingelement is used for the backlight unit 903, to which current is suppliedthrough a terminal 906.

As the light-emitting element, a light-emitting element including theorganic compound of one embodiment of the present invention ispreferably used. By including the light-emitting element, the backlightof the liquid crystal display device can have low power consumption.

FIG. 9 illustrates an example of a desk lamp which is one embodiment ofthe present invention. The desk lamp illustrated in FIG. 9 includes ahousing 2001 and a light source 2002, and a lighting device including alight-emitting element is used as the light source 2002.

FIG. 10 illustrates an example of an indoor lighting device 3001. Alight-emitting element including the organic compound of one embodimentof the present invention is preferably used in the lighting device 3001.

An automobile which is one embodiment of the present invention isillustrated in FIG. 11. In the automobile, light-emitting elements areused for a windshield and a dashboard. Display regions 5000 to 5005 areprovided by using the light-emitting elements. The light-emittingelements preferably include the organic compound of one embodiment ofthe present invention, in which case the light-emitting elements canhave low power consumption. This also suppresses power consumption ofthe display regions 5000 to 5005, showing suitability for use in anautomobile.

The display regions 5000 and 5001 are display devices which are providedin the automobile windshield and which include the light-emittingelements. When a first electrode and a second electrode are formed ofelectrodes having light-transmitting properties in these light-emittingelements, what is called a see-through display device, through which theopposite side can be seen, can be obtained. Such a see-through displaydevice can be provided even in the automobile windshield, withouthindering the vision. Note that in the case where a transistor fordriving or the like is provided, a transistor having alight-transmitting property, such as an organic transistor using anorganic semiconductor material or a transistor using an oxidesemiconductor, is preferably used.

The display region 5002 is a display device which is provided in apillar portion and which includes the light-emitting element. Thedisplay region 5002 can compensate for the view hindered by the pillarportion by showing an image taken by an imaging unit provided in the carbody. Similarly, a display region 5003 provided in the dashboard cancompensate for the view hindered by the car body by showing an imagetaken by an imaging unit provided in the outside of the car body, whichleads to elimination of blind areas and enhancement of safety. Showingan image so as to compensate for the area which a driver cannot seemakes it possible for the driver to confirm safety easily andcomfortably.

The display region 5004 and the display region 5005 can provide avariety of kinds of information such as navigation information, aspeedometer, a tachometer, a mileage, a fuel meter, a gearshiftindicator, and air-condition setting. The content or layout of thedisplay can be changed freely by a user as appropriate. Note that suchinformation can also be shown by the display regions 5000 to 5003. Thedisplay regions 5000 to 5005 can also be used as lighting devices.

FIGS. 12A and 12B illustrate an example of a foldable tablet terminal.FIG. 12A illustrates the tablet terminal which is unfolded. The tabletterminal includes a housing 9630, a display portion 9631 a, a displayportion 9631 b, a display mode switch 9034, a power switch 9035, apower-saving mode switch 9036, and a clip 9033. Note that in the tabletterminal, one or both of the display portion 9631 a and the displayportion 9631 b is/are formed using a light-emitting device whichincludes the light-emitting element containing the organic compound ofone embodiment of the present invention.

Part of the display portion 9631 a can be a touchscreen region 9632 aand data can be input when a displayed operation key 9637 is touched.Although half of the display portion 9631 a has only a display functionand the other half has a touchscreen function, one embodiment of thepresent invention is not limited to the structure. The whole displayportion 9631 a may have a touchscreen function. For example, a keyboardcan be displayed on the entire region of the display portion 9631 a sothat the display portion 9631 a is used as a touchscreen, and thedisplay portion 9631 b can be used as a display screen.

Like the display portion 9631 a, part of the display portion 9631 b canbe a touchscreen region 9632 b. When a switching button 9639 forshowing/hiding a keyboard on the touchscreen is touched with a finger, astylus, or the like, the keyboard can be displayed on the displayportion 9631 b.

Touch input can be performed in the touchscreen region 9632 a and thetouchscreen region 9632 b at the same time.

The display mode switch 9034 can switch the display between portraitmode, landscape mode, and the like, and between monochrome display andcolor display, for example. The power-saving mode switch 9036 cancontrol display luminance in accordance with the amount of externallight in use of the tablet terminal sensed by an optical sensorincorporated in the tablet terminal. Another sensing device including asensor such as a gyroscope or an acceleration sensor for sensinginclination may be incorporated in the tablet terminal, in addition tothe optical sensor.

Although FIG. 12A illustrates an example in which the display portion9631 a and the display portion 9631 b have the same display area, oneembodiment of the present invention is not limited to the example. Thedisplay portion 9631 a and the display portion 9631 b may have differentdisplay areas and different display quality. For example, higherresolution images may be displayed on one of the display portions 9631 aand 9631 b.

FIG. 12B illustrates the tablet terminal which is folded. The tabletterminal in this embodiment includes the housing 9630, a solar cell9633, a charge and discharge control circuit 9634, a battery 9635, and aDCDC converter 9636. In FIG. 12B, a structure including the battery 9635and the DCDC converter 9636 is illustrated as an example of the chargeand discharge control circuit 9634.

Since the tablet terminal is foldable, the housing 9630 can be closedwhen the tablet terminal is not in use. As a result, the display portion9631 a and the display portion 9631 b can be protected, therebyproviding a tablet terminal with high endurance and high reliability forlong-term use.

The tablet terminal illustrated in FIGS. 12A and 12B can have otherfunctions such as a function of displaying various kinds of data (e.g.,a still image, a moving image, and a text image), a function ofdisplaying a calendar, a date, the time, or the like on the displayportion, a touch-input function of operating or editing the datadisplayed on the display portion by touch input, and a function ofcontrolling processing by various kinds of software (programs).

The solar cell 9633 provided on a surface of the tablet terminal cansupply power to the touchscreen, the display portion, a video signalprocessing portion, or the like. Note that a structure in which thesolar cell 9633 is provided on one or both surfaces of the housing 9630is preferable because the battery 9635 can be charged efficiently.

The structure and operation of the charge and discharge control circuit9634 illustrated in FIG. 12B are described with reference to a blockdiagram of FIG. 12C. FIG. 12C illustrates the solar cell 9633, thebattery 9635, the DCDC converter 9636, a converter 9638, switches SW1 toSW3, and a display portion 9631. The battery 9635, the DCDC converter9636, the converter 9638, and the switches SW1 to SW3 correspond to thecharge and discharge control circuit 9634 illustrated in FIG. 12B.

First, description is made on an example of the operation in the casewhere power is generated by the solar cell 9633 with the use of externallight. The voltage of the power generated by the solar cell is raised orlowered by the DCDC converter 9636 so as to be voltage for charging thebattery 9635. Then, when power from the solar cell 9633 is used for theoperation of the display portion 9631, the switch SW1 is turned on andthe voltage of the power is raised or lowered by the converter 9638 soas to be voltage needed for the display portion 9631. When images arenot displayed on the display portion 9631, the switch SW1 is turned offand the switch SW2 is turned on so that the battery 9635 is charged.

Although the solar cell 9633 is described as an example of a powergeneration unit, the power generation unit is not particularly limited,and the battery 9635 may be charged by another power generation unitsuch as a piezoelectric element or a thermoelectric conversion element(Peltier element). The battery 9635 may be charged by a non-contactpower transmission module capable of performing charging by transmittingand receiving power wirelessly (without contact), or another charge unitused in combination, and the power generation unit is not necessarilyprovided.

Note that the organic compound of one embodiment of the presentinvention can be used for an organic thin-film solar cell. Specifically,the organometallic complex can be used in a carrier-transport layersince the organometallic complex has a carrier-transport property. Theorganometallic complex can be photoexcited and hence can be used in apower generation layer.

One embodiment of the present invention is not limited to the tabletterminal having the shape illustrated in FIGS. 12A to 12C as long as thedisplay portion 9631 is included.

FIGS. 13A to 13C illustrate a foldable portable information terminal9310. FIG. 13A illustrates the portable information terminal 9310 thatis opened. FIG. 13B illustrates the portable information terminal 9310that is being opened or being folded. FIG. 13C illustrates the portableinformation terminal 9310 that is folded. The portable informationterminal 9310 is highly portable when folded. When the portableinformation terminal 9310 is opened, a seamless large display region ishighly browsable.

A display panel 9311 is supported by three housings 9315 joined togetherby hinges 9313. Note that the display panel 9311 may be a touch panel(an input/output device) including a touch sensor (an input device). Bybending the display panel 9311 at a connection portion between twohousings 9315 with the use of the hinges 9313, the portable informationterminal 9310 can be reversibly changed in shape from an opened state toa folded state. The light-emitting device of one embodiment of thepresent invention can be used for the display panel 9311. A displayregion 9312 in the display panel 9311 is a display region that ispositioned at the side surface of the portable information terminal 9310that is folded. On the display region 9312, information icons, fileshortcuts of frequently used applications or programs, and the like canbe displayed, and confirmation of information and start of applicationcan be smoothly performed.

Example 1 Synthesis Example 1

In this synthesis example, synthesis of(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine, which is used asan intermediate for synthesizing the organic compound of one embodimentof the present invention, is described in detail. The structural formulaof (6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine is shownbelow.

Step 1: Synthesis of 6-iodobenzo[b]naphtho[1,2-d]furan

Into a 500 mL three-neck flask were put 8.5 g (39 mmol) ofbenzo[b]naphtho[1,2-d]furan, and the air in the flask was replaced withnitrogen. Then, 195 mL of tetrahydrofuran (THF) was added thereto. Then,25 mL (40 mmol) of n-butyllithium (a 1.59 mol/L n-hexane solution) wasdropped into this solution. After the dropping, the resulting solutionwas stirred at room temperature for 1 hour. After that, the resultingsolution was cooled to −75° C. Then, a solution in which 10 g (40 mmol)of iodine had been dissolved in 40 mL of THF was dropped into thissolution. After the dropping, the resulting solution was stirred for 17hours while the temperature of the solution was returned to roomtemperature. After the stirring, an aqueous solution of sodiumthiosulfate was added to the mixture, and the resulting mixture wasstirred for 1 hour. Then, the organic layer of the mixture was washedwith water and dried with magnesium sulfate. After the drying, themixture was gravity-filtered to give a solution. The resulting solutionwas suction-filtered through Florisil (Catalog No. 066-05265 produced byWako Pure Chemical Industries, Ltd.) and Celite (Catalog No. 537-02305produced by Wako Pure Chemical Industries, Ltd.) to give a filtrate. Theresulting filtrate was concentrated to give a solid. The resulting solidwas recrystallized from toluene to give 6.0 g (18 mmol) of a whitepowder of the objective substance in a yield of 45%. A synthesis schemeof Step 1 is shown below.

Step 2: Synthesis of 6-phenylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 6.0 g (18 mmol) of6-iodobenzo[b]naphtho[1,2-d]furan, 2.4 g (19 mmol) of phenylboronicacid, 70 mL of toluene, 20 mL of ethanol, and 22 mL of an aqueoussolution of potassium carbonate (2.0 mol/L). This mixture was degassedby being stirred while the pressure was reduced. After the degassing,the air in the flask was replaced with nitrogen, and then 480 mg (0.42mmol) of tetrakis(triphenylphosphine)palladium(0) was added to themixture. The resulting mixture was stirred at 90° C. under a nitrogenstream for 12 hours. After a predetermined period of time, water wasadded to the mixture, an organic layer and an aqueous layer wereseparated, and the aqueous layer was subjected to extraction withtoluene. The extracted solution and an organic layer were combined, andthe mixture was washed with water and then dried with magnesium sulfate.The mixture was gravity-filtered to give a filtrate. The resultingfiltrate was concentrated to give a solid, and the resulting solid wasdissolved in toluene. The resulting solution was suction-filteredthrough Celite (Catalog No. 531-16855 produced by Wako Pure ChemicalIndustries, Ltd.), Florisil (Catalog No. 540-00135 produced by Wako PureChemical Industries, Ltd.), and alumina to give a filtrate. Theresulting filtrate was concentrated to give a solid. The resulting solidwas recrystallized from toluene to give a 4.9 g (17 mmol) of a whitesolid of the objective substance in a yield of 93%. A synthesis schemeof Step 2 is shown below.

Step 3: Synthesis of 8-iodo-6-phenylbenzo[b]naphtho[1,2,d]furan

Into a 300 mL three-neck flask was put 4.9 g (17 mmol) of6-phenylbenzo[b]naphtho[1,2-d]furan, and the air in the flask wasreplaced with nitrogen. Then, 87 mL of tetrahydrofuran (THF) was addedthereto. The resulting solution was cooled to −75° C. Then, 11 mL (18mmol) of n-butyllithium (a 1.59 mol/L n-hexane solution) was droppedinto the solution. After the dropping, the resulting solution wasstirred at room temperature for 1 hour. After that, the solution wascooled to −75° C. Then, a solution in which 4.6 g (18 mmol) of iodinehad been dissolved in 18 mL of THF was dropped into the resultingsolution. The resulting solution was stirred for 17 hours while thetemperature of the solution was returned to room temperature. After thestirring, an aqueous solution of sodium thiosulfate was added to themixture, and the resulting mixture was stirred for one hour. Then, anorganic layer of the mixture was washed with water and dried withmagnesium sulfate. The mixture was gravity-filtered to give a filtrate.The resulting filtrate was suction-filtered through Celite (Catalog No.531-16855 produced by Wako Pure Chemical Industries, Ltd.), Florisil(Catalog No. 540-00135 produced by Wako Pure Chemical Industries, Ltd.),and alumina to give a filtrate. The resulting filtrate was concentratedto give a solid. The resulting solid was recrystallized from toluene togive 3.7 g (8.8 mmol) of an objective white solid in a yield of 53%. Asynthesis scheme of Step 3 is shown below.

Step 4: Synthesis of (6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)phenylamine

Into a 200 mL three-neck flask were added 5.0 g (12 mmol) of8-iodo-6-phenylbenzo[b]naphtho[1,2-d]furan and 2.9 g (30 mmol) of sodiumtert-bitoxide. The air in the flask was replaced with nitrogen. Afterthat, 60 mL of toluene and 1.4 g (13 mmol) of aniline, and 0.4 mL oftri(tert-butyl)phosphine (10 wt % hexane solution) were added. Afterthis mixture was degassed under reduced pressure, the temperature wasset at 60° C. under a nitrogen stream, 60 mg (0.1 mmol) ofbis(dibenzylideneacetone)palladium(0) was added, and this mixture wasstirred at 60° C. for 40 minutes. After the stirring, the obtainedmixture was washed with water and a saturated aqueous solution of sodiumchloride, and the organic layer was dried with magnesium sulfate. Afterthe magnesium sulfate was removed by gravity filtration, the obtainedfiltrate was concentrated to give a white solid. This solid was purifiedby silica gel column chromatography (a developing solvent was a mixedsolvent of toluene:hexane=1:2) to give 3.5 g of a white solid of anobjective substance in a yield of 77%. A synthesis scheme of Step 4 isshown below.

¹H NMR data of the obtained white solid are shown below. In addition,FIGS. 14A and 14B show the ¹H-NMR charts. These results indicate that(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine, which is theorganic compound of one embodiment of the present invention, wasobtained.

¹H-NMR (chloroform-d, 500 MHz): δ=6.23 (s, 1H), 7.04 (t, J=7.5 Hz, 1H),7.24-7.26 (m, 2H), 7.34-7.41 (m, 4H), 7.47 (t, J=8.0 Hz, 1H), 7.54-7.60(m, 3H), 7.74 (t, J=7.5 Hz, 1H), 7.95 (d, J=6.5 Hz, 2H), 7.99 (dd,J1=1.5 Hz, J2=7.0 Hz, 1H), 8.03 (s, 1H), 8.08 (d, J=8.0 Hz, 1H), 8.66(d, J=9.0 Hz, 1H)

Example 2

In this example, a synthesis method of(9,9-dimethyl-9H-fluorene-2,7-diyl)bis(N,6-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine(abbreviation: BnfA2F), which is the organic compound of one embodimentof the present invention and represented by the structural formula (148)in Embodiment, is described. The structural formula of BnfA2F is shownbelow.

Step 1: Synthesis of(9,9-dimethyl-9H-fluorene-2,7-diyl)bis(N,6,-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine(Abbreviation: BnfA2F)

Into a 200 mL three-neck flask were added 0.89 g (2.5 mmol) of2,7-dibromo-9,9-dimethyl-9H-fluorene, 1.9 g (5.0 mmol) of(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine, 0.34 g (0.80mmol) of(S)-(6,6′-dimethoxybiphenyl-2,2′-diyl)bis(diisopropylphosphine)(cBRIDP(registered trademark)), and 1.7 g (18 mmol) of sodium tert-butoxide.The air in the flask was replaced with nitrogen, and then 15 mL oftoluene was added. This mixture was degassed under reduced pressure, thetemperature was set at 80° C. under a nitrogen stream, 72 mg (0.20 mmol)of allylpalladium(II) chloride dimer was added, and this mixture wasstirred at 80° C. for 2 hours 40 minutes. After the stirring, theobtained mixture was washed with water and a saturated aqueous solutionof sodium chloride, and the organic layer was dried with magnesiumsulfate. After the magnesium sulfate was removed by gravity filtration,and the obtained filtrate was concentrated to give a brown solid. Thesolid was purified by silica gel column chromatography (the developingsolvent was toluene and hexane (toluene:hexane=1:1)) to give 1.4 g of ayellow solid of an objective substance in a yield of 60%. A synthesisscheme of Step 1 is shown below.

¹H NMR data of the obtained yellow solid are shown below. In addition,FIGS. 15A and 15B show the ¹H-NMR charts. These results indicate thatBnfA2F, which is the organic compound of one embodiment of the presentinvention, was obtained.

¹H NMR (dichloromethane-d2, 500 MHz): δ=1.14 (s, 6H), 7.08-7.14 (m,10H), 7.18-7.25 (m, 8H), 7.28-7.31 (m, 4H), 7.39 (dd, J1=2.5 Hz, J2=7.8Hz, 4H), 7.42 (t, J=8.0 Hz, 2H), 8.0 (t, J=8.0 Hz, 2H), 7.60 (d, J=8.0Hz, 2H), 7.72 (dt, J1=1.0 Hz, J2=8.0 Hz, 2H), 8.00 (s, 2H), 8.05 (d,J=8.0 Hz, 2H), 8.20 (dd, J1=1.0 Hz, J2=8.0 Hz, 2H), 8.65 (d, J=8.0 Hz,2H)

By a train sublimation method, 1.4 g of BnfA2F, which was the obtainedsolid, was purified. In the purification by sublimation, the solid washeated at a temperature from 380° C. to 390° C. for 16 hours under apressure of 3.6 Pa with a flow rate of argon of 15 mL/min. After thepurification by sublimation, 1.3 g of a yellow solid, which was BnfA2F,was obtained at a collection rate of 90%.

Example 3 Synthesis Example 3

In this synthesis example, a synthesis method ofN,N′-(7,7-diphenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 5,9BnfA2BzFL), which is the organic compound of oneembodiment of the present invention and represented by the structuralformula (101) in Embodiment, is exemplified in detail. The structuralformula of 5,9BnfA2BzFL is shown below.

Step 1: Synthesis of Ethyl 2-(1-naphthalene)phenyl-benzoate

Into a 1000 mL three-neck flask was put 15.9 g (57.6 mmol) of2-bromoethyl benzoate, and the air in the flask was replaced withnitrogen. Into the flask, 200.0 mL of toluene, 70.0 mL of ethanol, 11.2g (65.1 mmol) of 1-naphthaleneboronic acid, 6.8 g (64.4 mmol) of sodiumcarbonate, and 63.0 mL of water were added. To the mixture was added 0.3mg (0.3 mmol) of tetrakis(triphenylphosphine)palladium(0), thetemperature was set at 80° C., and stirring was performed for 9.4 hours.After the stirring, water was added to the mixture, an organic layer andan aqueous layer were separated, and the aqueous layer was subjected toextraction once with toluene and subjected to extraction twice withethyl acetate. The extracted solution was combined with the organiclayer and dried with magnesium sulfate. The obtained mixture wassubjected to gravity filtration, so that magnesium sulfate was removed,and the obtained filtrate was concentrated to give a solid. The obtainedsolid was purified by silica gel column chromatography (the developingsolvent was toluene). The obtained fraction was concentrated to give14.1 g of an objective substance in a yield of 88%. A synthesis schemeof Step 1 is shown below.

Step 2: Synthesis of {2-(1-naphthalene)phenyl}-diphenyl-methanol

Into a 500 mL three-neck flask was put 5.0 g (18.1 mmol) of ethyl2-(1-naphthalene)phenyl-benzoate, and the air in the flask was replacedwith nitrogen. Into the flask was put 130.0 mL of tetrahydrofuran, andthe flask was cooled down by iced water, and then 48.0 mL (48.0 mmol) ofa tetrahydrofuran solution of phenylmagnesiumbromide was put therein.After the temperature was gradually returned to room temperature,stirring was performed at 70° C. for 2 hours. After the stirring, 1.0Mhydrochloric acid was put, and stirring was performed for 30 minutes.After the stirring, water and ethyl acetate were added, and the mixturewas separated into an organic layer and an aqueous layer, and theaqueous layer was subjected to extraction with ethyl acetate twice. Theobtained solution of the extract and the organic layer were combined andwashed with a saturated aqueous solution of sodium chloride, an organiclayer and an aqueous layer were separated, and then the organic layerwas dried with magnesium sulfate. The mixture obtained was gravityfiltered to remove the magnesium sulfate, and the filtrate wasconcentrated to give an oily substance. The obtained oily substance waspurified by silica gel column chromatography (the developing solvent washexane and toluene (hexane:toluene=1:1)). The obtained fraction wasconcentrated to give 3.9 g of an objective substance in a yield of 56%.A synthesis scheme of Step 2 is shown below.

Step 3: Synthesis of 7,7-dipenyl-7H-benzo[C]fluorene

Into a 500 mL three-neck flask was put 3.9 g (10.0 mmol) of{2-(1-naphthalene)phenyl}-diphenyl-methanol. After that, 23.0 mL ofacetic acid was added, and stirring was performed at 110° C. for 7.0hours. After the stirring, water and toluene were added to the mixture,and an aqueous layer was subjected to extraction with toluene. Theextracted solution and an organic layer were combined and put into a 500mL Mayer flask. An aqueous solution of sodium hydrogen carbonate wasadded to the mixture, and the stirring was performed for 30 minutes.After the stirring, the aqueous layer and the organic layer wereseparated, and then the organic layer was dried with magnesium sulfate.This mixture was gravity filtered, and the obtained filtrate wasconcentrated to give a solid. The obtained solid was purified by silicagel column chromatography (the developing solvent was hexane and toluene(hexane:toluene=3:1)), and the obtained fraction was concentrated togive a solid. The obtained solid was washed with hexane to give 2.7 g ofan objective compound in a yield of 72%. A synthesis scheme of Step 3 isshown below.

Step 4: Synthesis of 5,9-diiodo-7,7-diphenyl-7H-benzo[C]fluorene

Into a 100 mL three-neck flask were put 1.7 g (4.7 mmol) of7,7-dipenyl-7H-benzo[C]fluorene, 2.4 g (9.4 mmol) of iodine, 2.2 g (9.6mmol) of orthoperiodic acid, 7.0 mL of acetic acid, 1.4 mL of water, andone drop of concentrated sulfuric acid, and stirring was performed at60° C. for 4.5 hours. After the stirring, the temperature was set at 0°C., and an aqueous solution of sodium thiosulfate was added. After that,water and toluene were added to the mixture, an organic layer and anaqueous layer were separated, and the aqueous layer was subjected toextraction with toluene twice. The extracted solution was combined withthe organic layer and dried with magnesium sulfate. The mixture obtainedwas gravity filtered to remove the magnesium sulfate, and the filtratewas concentrated to obtain an oily substance. The obtained solid waspurified by silica gel column chromatography (the developing solvent washexane and toluene (hexane:toluene=5:1)), and the obtained fraction wasconcentrated to give a solid. The obtained solid was recrystallized fromtoluene to give 0.9 g of an objective compound in a yield of 30%. Asynthesis scheme of Step 4 is shown below.

Step 5: Synthesis ofN,N′-(7,7-dipenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 5,9BnfA2BzFL)

Into a 100 mL three-neck flask were put 1.1 g (2.8 mmol) of(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl) phenylamine, 0.8 g (1.3 mmol)of 5,9-diiodo-7,7-dipenyl-7H-benzo[C]fluorene, and 0.4 g (3.9 mmol) ofsodium tert-butoxide, and the air in the flask was replaced withnitrogen. To this mixture were added 13.0 mL of xylene and 0.5 mL of a10% hexane solution of tri(tert-butyl)phosphine. The temperature of thismixture was set to 80° C., 39.2 mg (0.1 mmol) ofbis(dibenzylideneacetone)palladium(0) was added, and stirring wasperformed for 3.0 hours. After the stirring, 21.0 mg (0.1 mmol) ofbis(dibenzylideneacetone)palladium(0) was added, and stirring wasperformed at 110° C. for 1.0 hour. After the stirring, toluene was addedand heating was performed. After that, suction filtration was performedthrough Florisil (Catalog No. 066-05265 produced by Wako Pure ChemicalIndustries, Ltd.), Celite (Catalog No. 537-02305 produced by Wako PureChemical Industries, Ltd.), and alumina to give a filtrate. The obtainedfiltrate was concentrated to give an oily substance. The obtained oilysubstance was purified by silica gel column chromatography (thedeveloping solvent was hexane and toluene (hexane:toluene=3:2)). Theobtained fraction was concentrated to give a solid. The obtained solidwas recrystallized from toluene to give 1.1 g of an objective yellowsolid in a yield of 76%. By a train sublimation method, 1.1 g of theobtained yellow solid was purified at 330° C. under a pressure of4.4×10⁻² Pa. After the purification by sublimation, 0.6 g of anobjective yellow solid was obtained at a collection rate of 53%. Asynthesis scheme of Step 5 is shown below.

An analysis result by nuclear magnetic resonance (¹H-NMR) spectroscopyof the obtained yellow solid is described below. In addition, FIGS. 16Aand 16B show the ¹H-NMR charts. These results indicate that5,9BnfA2BzFL, which is the organic compound of one embodiment of thepresent invention, was obtained in this synthesis example.

¹H NMR (CDC13, 300 MHz): δ=6.29 (dd, J=7.2 Hz, 2H), 6.49 (dd, J=7.2 Hz,4H), 6.76 (d, J=7.2 Hz, 4H), 6.89-7.35 (m, 28H), 7.53-7.74 (m, 5H), 7.91(d, J=4.5 Hz, 2H), 8.01-8.06 (m, 4H), 8.12 (d, J=7.5 Hz, 1H), 8.32 (d,J=8.4 Hz, 1H), 8.60 (dd, J=3.6 Hz, 8.3 Hz, 2H), 8.90 (d, J=11.7 Hz, 1H)

Thermogravimetry-differential thermal analysis (TG-DTA) of obtained5,9BnfA2BzFL was performed. A high vacuum differential type differentialthermal balance (TG/DTA 2410SA, manufactured by Bruker AXS K.K.) wasused for the measurement. The measurement was carried out under anitrogen stream (a flow rate of 200 mL/min) and a normal pressure at atemperature rising rate of 10° C./min. The relationship between weightand temperature (thermogravimetry) shows that the 5% weight losstemperature is 458° C., which is indicative of favorable heatresistance.

Next, the ultraviolet-visible absorption spectrum (hereinafter, simplyreferred to as “absorption spectrum”) and emission spectrum of a toluenesolution and a solid thin film of 5,9BnfA2BzFL were measured. Theabsorption spectra were measured using an ultraviolet-visible lightspectrophotometer (V550 type manufactured by JASCO Corporation). Theemission spectra were measured using a fluorescence spectrophotometer(FS920 manufactured by Hamamatsu Photonics K.K.). FIGS. 17A and 17B showthe obtained absorption spectra and emission spectra of and the toluenesolution and the solid thin film of 5,9BnfA2BzFL. Note that FIGS. 17Aand 17B show the results of the toluene solution and the solid thin filmof 5,9BnfA2BzFL, respectively.

As shown in FIGS. 17A and 17B, an emission peak of the toluene solutionof 5,9BnfA2BzFL, which is the organic compound of one embodiment of thepresent invention, was observed at 450 nm, an emission peak of the solidthin film of 5,9BnfA2BzFL was observed at 467 nm, and thus blue lightemission was observed.

Example 4

In this example, the light-emitting element 1 which is thelight-emitting element of one embodiment of the present invention anddescribed in Embodiment is described in detail. Structural formulae oforganic compounds used for the light-emitting element 1 are shown below.

(Manufacturing Method of Light-Emitting Element 1)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed over a glass substrate by a sputtering method, so that the firstelectrode 101 was formed. The thickness of the first electrode 101 wasset to 70 nm and the area of the electrode was set to 2 mm×2 mm.

Next, in pretreatment for forming the light-emitting element over thesubstrate, a surface of the substrate was washed with water and baked at200° C. for one hour, and then UV ozone treatment was performed for 370seconds.

Then, the substrate was transferred into a vacuum evaporation apparatusin which the pressure was reduced to approximately 10⁻⁴ Pa, and vacuumbaking at 170° C. for 30 minutes was conducted in a heating chamber ofthe vacuum evaporation apparatus, and then the substrate was cooled downfor approximately 30 minutes.

Then, the substrate over which the first electrode 101 was formed wasfixed to a substrate holder provided in the vacuum evaporation apparatussuch that the surface on which the first electrode 101 was formed faceddownward. After that, over the first electrode 101,9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation:PCzPA) represented by the above structural formula (i) andmolybdenum(VI) oxide were co-evaporated by an evaporation method usingresistance heating, so that the hole-injection layer 111 was formed. Thehole-injection layer 111 was formed with a thickness of 10 nm such thatthe weight ratio of PCzPA to molybdenum oxide was 4:2.

Next, a film of PCzPA represented by the above structural formula wasformed to a thickness of 20 nm over the hole-injection layer 111 to formthe hole-transport layer 112.

Furthermore, 7-[4-(10-phenyl-9-anthry)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA) which is represented by the above structuralformula (ii) andN,N′-(7,7-diphenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 5,9BnfA2BzFL) which is represented by the abovestructural formula (iii) were co-evaporated over the hole-transportlayer 112 to form the light-emitting layer 113. The light-emitting layer113 was formed to a thickness of 25 nm such that the weight ratio ofcgDBCzPA to 5,9BnfA2BzFL was 1:0.03.

Then, the electron-transport layer 114 was formed over thelight-emitting layer 113 in such a way that a 10-nm-thick film ofcgDBCzPA was formed and a 15-nm-thick film of bathophenanthroline(abbreviation: BPhen) represented by the above structural formula (iv)was formed.

After the formation of the electron-transport layer 114, lithiumfluoride (LiF) was deposited by evaporation to a thickness of 1 nm asthe electron-injection layer 115 and aluminum was deposited byevaporation to a thickness of 200 nm as the second electrode 102. Thus,the light-emitting element 1 in this example was fabricated. The elementstructure of the light-emitting element 1 is shown in a table below.

TABLE 1 Hole-injection Hole-transport Light-emitting Electron-transportElectron-injection layer layer layer layer layer PCzPA:MoOx  PCzPAcgDBCzPA:5,9BnfA2BzFL 2mDBTBPDBq- II BPhen LiF 2:1 1:0.03  10 nm 20 nm25 nm 10 nm 15 nm 1 nm

The light-emitting element 1 was sealed using a glass substrate in aglove box containing a nitrogen atmosphere so as not to be exposed tothe air (specifically, a sealing material was applied to surround theelement and UV treatment and heat treatment at 80° C. for 1 hour wereperformed at the time of sealing). Then, the initial characteristics andreliability of the light-emitting element were measured. Note that themeasurements were performed at room temperature (in an atmosphere keptat 25° C.).

FIG. 18 shows luminance-current density characteristics of thelight-emitting element 1. FIG. 19 shows current efficiency-luminancecharacteristics of the light-emitting element 1. FIG. 20 showsluminance-voltage characteristics of the light-emitting element 1. FIG.21 shows current-voltage characteristics of the light-emitting element1. FIG. 22 shows chromaticity coordinates of the light-emitting element1. FIG. 23 shows external quantum efficiency-luminance characteristicsof the light-emitting element 1. FIG. 24 shows an emission spectrum ofthe light-emitting element 1. Table 2 shows main characteristics of thelight-emitting element 1 at around 1000 cd/m².

TABLE 2 External Current Current quantum Voltage density ChromaticityChromaticity efficiency efficiency (V) (mA/cm²) x y (cd/A) (%) 3.0 120.14 0.13 8.2 8.1

It was found from FIGS. 18 to 24 and Table 2 that the light-emittingelement of one embodiment of the present invention has favorablecharacteristics of efficient blue light emission with favorablechromaticity.

Example 5

In this example, the light-emitting element 2 which is thelight-emitting element of one embodiment of the present invention anddescribed in Embodiment is described in detail. Structural formulae oforganic compounds used for the light-emitting element 2 are shown below.

(Manufacturing Method of Light-Emitting Element 2)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed over a glass substrate by a sputtering method, so that the firstelectrode 101 was formed. The thickness of the first electrode 101 wasset to 70 nm and the area of the electrode was set to 2 mm×2 mm.

Next, in pretreatment for forming the light-emitting element over thesubstrate, a surface of the substrate was washed with water and baked at200° C. for one hour, and then UV ozone treatment was performed for 370seconds.

Then, the substrate was transferred into a vacuum evaporation apparatusin which the pressure was reduced to approximately 10⁻⁴ Pa, and vacuumbaking at 170° C. for 30 minutes was conducted in a heating chamber ofthe vacuum evaporation apparatus, and then the substrate was cooled downfor approximately 30 minutes.

Then, the substrate over which the first electrode 101 was formed wasfixed to a substrate holder provided in the vacuum evaporation apparatussuch that the surface on which the first electrode 101 was formed faceddownward. After that, over the first electrode 101,3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn)represented by the above structural formula (v) and molybdenum(VI) oxidewere deposited by co-evaporation by an evaporation method usingresistance heating, so that the hole-injection layer 111 was formed. Thehole-injection layer 111 was formed to a thickness of 10 nm such thatthe weight ratio of PCPPn to molybdenum oxide was 4:2.

Next, a film of PCzPA represented by the above structural formula wasformed with a thickness of 20 nm over the hole-injection layer 111 toform the hole-transport layer 112.

Furthermore, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA) which is represented by the above structuralformula (ii) andN,N′-(7,7-diphenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-c]furan)-8-amine](abbreviation: 5,9BnfA2BzFL) which is represented by the abovestructural formula (iii) were co-evaporated over the hole-transportlayer 112 to form the light-emitting layer 113. The light-emitting layer113 was formed to a thickness of 25 nm such that the weight ratio ofcgDBCzPA to 5,9BnfA2BzFL was 1:0.03.

Then, the electron-transport layer 114 was formed over thelight-emitting layer 113 in such a way that a 10-nm-thick film ofcgDBCzPA was formed and a 15-nm-thick film of bathophenanthroline(abbreviation: BPhen) represented by the above structural formula (iv)was formed.

After the formation of the electron-transport layer 114, lithiumfluoride (LiF) was deposited by evaporation to a thickness of 1 nm asthe electron-injection layer 115 and aluminum was deposited byevaporation to a thickness of 200 nm as the second electrode 102. Thus,the light-emitting element 2 in this example was fabricated. The elementstructure of the light-emitting element 2 is shown in a table below.

TABLE 3 Hole-injection Hole-transport Light-emitting Electron-transportElectron-injection layer layer layer layer layer PCPPn:MoOx PCPPncgDBCzPA:5,9BnfA2BzFL 2mDBTBPDBq- II BPhen LiF  2:1 1:0.03  10 nm 20 nm25 nm 10 nm 15 nm 1 nm

The light-emitting element 2 was sealed using a glass substrate in aglove box containing a nitrogen atmosphere so as not to be exposed tothe air (specifically, a sealing material was applied to surround theelement and UV treatment and heat treatment at 80° C. for 1 hour wereperformed at the time of sealing). Then, the initial characteristics andreliability of the light-emitting element were measured. Note that themeasurements were performed at room temperature (in an atmosphere keptat 25° C.).

FIG. 25 shows luminance-current density characteristics of thelight-emitting element 2. FIG. 26 shows current efficiency-luminancecharacteristics of the light-emitting element 2. FIG. 27 showsluminance-voltage characteristics of the light-emitting element 2. FIG.28 shows current-voltage characteristics of the light-emitting element2. FIG. 29 shows chromaticity coordinates of the light-emitting element2. FIG. 30 shows external quantum efficiency-luminance characteristicsof the light-emitting element 2. FIG. 31 shows an emission spectrum ofthe light-emitting element 2. Table 4 shows main characteristics of thelight-emitting element 2 at around 1000 cd/m².

TABLE 4 External Current Current quantum Voltage density ChromaticityChromaticity efficiency efficiency (V) (mA/cm²) x y (cd/A) (%) 3.0 5.70.14 0.12 10 11

It was found from FIGS. 25 to 31 and Table 4 that the light-emittingelement of one embodiment of the present invention has favorablecharacteristics of efficient blue light emission with favorablechromaticity.

Example 6

In this example, the light-emitting elements 3 and 4 each of which isthe light-emitting element of one embodiment of the present inventionand described in Embodiment are described in detail. Structural formulaeof organic compounds used for the light-emitting elements 3 and 4 areshown below. Note that the light-emitting elements 3 and 4 arelight-emitting elements in each of whichN,N-(7,7-diphenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation: 5,9BnfA2BzFL) which is the organic compound of oneembodiment of the present invention was used for part of thehole-transport layer.

(Manufacturing Method of Light-Emitting Element 3 and Light-EmittingElement 4)

First, a film of indium tin oxide containing silicon oxide (ITSO) wasformed over a glass substrate by a sputtering method, so that the firstelectrode 101 was formed. The thickness of the first electrode 101 wasset to 70 nm and the area of the electrode was set to 2 mm×2 mm.

Next, in pretreatment for forming the light-emitting element over thesubstrate, a surface of the substrate was washed with water and baked at200° C. for one hour, and then UV ozone treatment was performed for 370seconds.

Then, the substrate was transferred into a vacuum evaporation apparatusin which the pressure was reduced to approximately 10⁻⁴ Pa, and vacuumbaking at 170° C. for 30 minutes was conducted in a heating chamber ofthe vacuum evaporation apparatus, and then the substrate was cooled downfor approximately 30 minutes.

Next, the substrate provided with the first electrode 101 was fixed to asubstrate holder provided in the vacuum evaporation device such that thesurface on which the first electrode 101 was formed faced downward. Byan evaporation method using resistance heating2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN)represented by the above structural formula (vi) was deposited to athickness of 5 nm over the first electrode 101, whereby thehole-injection layer 111 was formed.

Next, over the hole-injection layer 111,N,N′-(7,7-dipenyl-7H-benzo[c]fluorene-5,9-diyl)bis[(N,6-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine]abbreviation: 5,9BnfA2BzFL) represented by the above structural formula(iii), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine(abbreviation: BBABnf) represented by the above structural formula(vii), and 3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carbazole(abbreviation: βNP2PC) were formed in this order. They were each formedto a thickness of 10 nm. Thus, the hole-transport layer 112 was formed.

Furthermore, over the hole-transport layer 112, the light-emitting layer113 was formed by co-evaporation of7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA) represented by the above structural formula(ii) and N,N′-bis(3-methylphenyl)-N,N′-bis[3-(9-penyl-9H-fluoren-9-yl)pheny]-pyrene-1,6-diamine(abbreviation: 1,6mMemFLPAPrn) represented by the above structuralformula (x). The light-emitting layer 113 was formed with a thickness of25 nm such that the weight ratio of cgDBCzPA to 1,6mMemFLPAPrn was1:0.03.

After that, over the light-emitting layer 113, cgDBCzPA was formed witha thickness of 10 nm, and bathophenanthroline (abbreviation: BPhen)represented by the above structural formula (v) was formed with athickness of 15 nm, whereby the electron-transport layer 114 was formed.

After the formation of the electron-transport layer 114, lithiumfluoride (LiF) was deposited by evaporation to a thickness of 1 nm asthe electron-injection layer 115 and aluminum was deposited byevaporation to a thickness of 200 nm as the second electrode 102. Thus,the light-emitting element 3 in this example was fabricated.

The light-emitting element 4 was fabricated in such a manner that4-naphthyl-4′,4′-diphenyltriphenylamine (abbreviation: BBAβNB)represented by the above structural formula (viii) is used for thehole-transport layer instead of BBABnf used for the hole-transport layerin the light-emitting element 3.

The element structures of the light-emitting element 3 and thelight-emitting element 4 are shown in a table below.

TABLE 5 Hole- injection layer Hole-transport layer Light-emitting layerElectron-transport layer 5 nm 10 nm 10 nm 10 nm 25 nm 10 nm 15 nm Light-HAT-CN 5,9BnfA2BzFL BBABnf βNP2PC cgDBCzPA:1,6mMemFLPAPrn cgDBCzPA BPhenemitting 1:0.03 element 3 Light- BBAβNB emitting element 4

The light-emitting element 3 and the light-emitting element 4 weresealed using a glass substrate in a glove box containing a nitrogenatmosphere so as not to be exposed to the air (specifically, a sealingmaterial was applied to surround the element and UV treatment and heattreatment at 80° C. for 1 hour were performed at the time of sealing).Then, the initial characteristics and reliability of the light-emittingelements were measured. Note that the measurements were performed atroom temperature (in an atmosphere kept at 25° C.).

FIG. 32 shows luminance-current density characteristics of thelight-emitting element 3 and the light-emitting element 4. FIG. 33 showscurrent efficiency-luminance characteristics of the light-emittingelement 3 and the light-emitting element 4. FIG. 34 showsluminance-voltage characteristics of the light-emitting element 3 andthe light-emitting element 4. FIG. 35 shows current-voltagecharacteristics of the light-emitting element 3 and the light-emittingelement 4. FIG. 36 shows external quantum efficiency-luminancecharacteristics of the light-emitting element 3 and the light-emittingelement 4. FIG. 37 shows chromaticity coordinates of the light-emittingelement 3 and the light-emitting element 4. FIG. 38 shows an emissionspectrum of the light-emitting element 3 and the light-emitting element4. Table 6 shows main characteristics of the light-emitting element 3and the light-emitting element 4 at around 1000 cd/m².

TABLE 6 Current External quantum Voltage Current density ChromaticityChromaticity efficiency efficiency (V) (mA/cm²) x y (cd/A) (%) Light-3.8 10 0.14 0.15 12 10 emitting element 3 Light- 3.4 6.6 0.14 0.15 12 11emitting element 4

FIG. 39 shows driving time-dependent change in luminance of thelight-emitting elements under the conditions where the current value wasset to 2 mA and the current density was constant. As shown in FIG. 39,it was found that the light-emitting elements 3 and 4 are long-lifetimelight-emitting elements in each of which a reduction in luminance withdriving time is small.

It was found from FIGS. 32 to 39 and Table 6 that the light-emittingelements of embodiments of the present invention are light-emittingelements having favorable characteristics.

Reference Example 1

In this reference example, a synthesis method ofN,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine(abbreviation: BBABnf) which was used in the light-emitting element 3 isdescribed. The structural formula of BBABnf is shown below.

Step 1: Synthesis of 6-iodobenzo[b]naphtho[1,2-d]furan

Into a 500 mL three-neck flask were put 8.5 g (39 mmol) ofbenzo[b]naphtho[1,2-d]furan, and the air in the flask was replaced withnitrogen. Then, 195 mL of tetrahydrofuran (THF) was added thereto. Thissolution was cooled to −75° C. Then, 25 mL (40 mmol) of n-butyllithium(a 1.59 mol/L n-hexane solution) was dropped into this solution. Afterthe dropping, the resulting solution was stirred at room temperature for1 hour. After a predetermined period of time, the resulting solution wascooled to −75° C. Then, a solution in which 10 g (40 mmol) of iodine hadbeen dissolved in 40 mL of THF was dropped into this solution. After thedropping, the resulting solution was stirred for 17 hours while thetemperature of the solution was returned to the room temperature. Afterthat, an aqueous solution of sodium thiosulfate was added to themixture, stirring was performed for 1 hour, and then the organic layerof the mixture was washed with water and dried with magnesium sulfate.After the drying, the mixture was gravity-filtered to give a solution.The resulting solution was suction-filtered through Florisil (CatalogNo. 066-05265 produced by Wako Pure Chemical Industries, Ltd.) andCelite (Catalog No. 537-02305 produced by Wako Pure Chemical Industries,Ltd.) to give a filtrate. The resulting filtrate was concentrated togive a solid. The resulting solid was recrystallized from toluene togive 6.0 g (18 mmol) of a white powder of the objective substance in ayield of 45%. A synthesis scheme of Step 1 is shown below.

Step 2: Synthesis of 6-phenylbenzo[b]naphtho[1,2-d]furan

Into a 200 mL three-neck flask were put 6.0 g (18 mmol) of6-iodobenzo[b]naphtho[1,2-d]furan synthesized in Step 1, 2.4 g (19 mmol)of phenylboronic acid, 70 mL of toluene, 20 mL of ethanol, and 22 mL ofan aqueous solution of potassium carbonate (2.0 mol/L). This mixture wasdegassed by being stirred while the pressure was reduced. After thedegassing, the air in the flask was replaced with nitrogen, and then 480mg (0.42 mmol) of tetrakis(triphenylphosphine)palladium(0) was added tothe mixture. The resulting mixture was stirred at 90° C. under anitrogen stream for 12 hours. After a predetermined time has passed,water was added to the mixture, and the aqueous layer was extracted withtoluene. The extracted solution and an organic layer were combined, andthe mixture was washed with water and then dried with magnesium sulfate.The mixture was gravity-filtered to give a filtrate. The resultingfiltrate was concentrated to give a solid, and the resulting solid wasdissolved in toluene. The resulting solution was suction-filteredthrough Celite (Catalog No. 531-16855 produced by Wako Pure ChemicalIndustries, Ltd.), Florisil (Catalog No. 540-00135 produced by Wako PureChemical Industries, Ltd.), and alumina to give a filtrate. Theresulting filtrate was concentrated to give a solid. The resulting solidwas recrystallized from toluene to give a 4.9 g (17 mmol) of a whitesolid of the objective substance in a yield of 93%. A synthesis schemeof Step 2 is shown below.

Step 3: Synthesis of 8-iodo-6-phenylbenzo[b]naphtho[1,2,d]furan

Into a 300 mL three-neck flask was put 4.9 g (17 mmol) of6-phenylbenzo[b]naphtho[1,2-d]furan synthesized in Step 2, and the airin the flask was replaced with nitrogen. Then, 87 mL of tetrahydrofuran(THF) was added thereto. The resulting solution was cooled to −75° C.Then, 11 mL (18 mmol) of n-butyllithium (a 1.59 mol/L n-hexane solution)was dropped into the solution. After the dropping, the resultingsolution was stirred at room temperature for 1 hour. After apredetermined period of time, the resulting solution was cooled to −75°C. Then, a solution in which 4.6 g (18 mmol) of iodine had beendissolved in 18 mL of THF was dropped into the resulting solution. Theresulting solution was stirred for 17 hours while the temperature of thesolution was returned to room temperature. After that, an aqueoussolution of sodium thiosulfate was added to the mixture, and stirringwas performed for 1 hour, and then the organic layer of the mixture waswashed with water and dried with magnesium sulfate. The mixture wasgravity-filtered to give a filtrate. The resulting filtrate wassuction-filtered through Celite (Catalog No. 531-16855 produced by WakoPure Chemical Industries, Ltd.), Florisil (Catalog No. 540-00135produced by Wako Pure Chemical Industries, Ltd.), and alumina to give afiltrate. The resulting filtrate was concentrated to give a solid. Theresulting solid was recrystallized from toluene to give 3.7 g (8.8 mmol)of an objective white solid in a yield of 53%. A synthesis scheme ofStep 3 is shown below.

Step 4: Synthesis of BBABnf

Into a 200 mL three-neck flask were put 2.1 g (5.0 mmol) of8-iodo-6-phenylbenzo[b]naphtho[1,2,-d]furan obtained in Step 3 inExample 1, 1.6 g (5.0 mmol) of bis(1,1′-bipenyl-4-yl)amine, 0.17 g (0.40mmol) of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (abbreviation:S-Phos), and 0.97 g (10 mmol) of sodium tert-butoxide. The air in theflask was replaced with nitrogen, and then 25 mL of xylene was added.After this mixture was degassed under reduced pressure, the temperaturewas set at 80° C. under a nitrogen stream, 0.12 g (0.20 mmol) ofbis(dibenzylideneacetone)palladium(0) was added, and this mixture wasstirred at 80° C. for 5.5 hours and further stirred at 100° C. for 5hours. After the stirring, the obtained mixture was washed with waterand a saturated aqueous solution of sodium chloride, and the organiclayer was dried with magnesium sulfate. After the magnesium sulfate wasremoved by gravity filtration, and the obtained filtrate wasconcentrated to give a brown solid. The obtained solid was dissolved intoluene and filtrated through Celite (Catalog No. 537-02305 produced byWako Pure Chemical Industries, Ltd.) and alumina. The obtained filtratewas concentrated to give 2.0 g of a yellow solid of BBABnf in a yield of67%. A synthesis scheme of Step 4 is shown below.

Reference Example 2

In this reference example, a synthesis method of4-naphthyl-4′,4″-diphenyltriphenylamine (abbreviation: BBAPNB) used forthe above light-emitting element 4 is described. The structural formulaof BBAPNB is shown below.

Step 1: Synthesis of 4-naphthyl-4′,4″-diphenyltriphenylamine(abbreviation: BBAPNB)

Into a 200 mL three-neck flask were put 2.3 g (7.1 mmol) ofbis(1,1′-biphenyl-4-yl)amine, 2.0 g (7.1 mmol) of2-(4-bromophenyl)naphthalene, 1.5 g (15 mmol) of sodium tert-butoxide(abbreviation: tert-BuONa), and 0.16 g (0.40 mmol) of2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (abbreviation: SPhos).The air in the flask was replaced with nitrogen, and then 35 mL ofxylene was added. After this mixture was degassed under reducedpressure, stirring was performed at 60° C. under a nitrogen stream, 0.12g (0.20 mmol) of bis(dibenzylideneacetone)palladium(0) was added, andthis mixture was stirred at 120° C. for 7 hours. After the stirring, theobtained mixture was washed with water and a saturated aqueous solutionof sodium chloride, and the organic layer was dried with magnesiumsulfate. After the magnesium sulfate was removed by gravity filtration,the obtained filtrate was concentrated to give a brown solid. The brownsolid was purified by high performance liquid chromatography (mobilephase: chloroform) to give 3.5 g of an objective light yellow solid in ayield of 93%. The synthesis scheme of this reaction is shown below.

¹H NMR data of the obtained light yellow solid are shown below. ¹H NMR(dichloromethane-d2, 500 MHz): δ=7.24 (d, J=9.0 Hz, 4H), 7.26 (d, J=8.5Hz, 2H), 7.31 (d, J=7.5 Hz, 2H), 7.42 (d, J=7.5 Hz, 4H), 7.45-7.50 (m,2H), 7.55 (d, J=8.5 Hz, 4H), 7.60 (d, J=7.5 Hz, 4H), 7.68 (d, J=8.5 Hz,2H), 7.76 (dd, J1=2.0 Hz, J2=8.5 Hz, 1H), 7.85 (d, J=8.0 Hz, 1H), 7.90(t, J=8.05 Hz, 2H), 8.05 (s, 1H)

In addition, FIGS. 40A and 40B show the ¹H-NMR charts. Note that FIG.40B is a chart where the range of from 7.00 ppm to 8.20 ppm in FIG. 40Ais enlarged.

By train sublimation, 3.5 g of the obtained light yellow solid waspurified. The purification by sublimation was carried out under apressure of 3.4 Pa, with a flow rate of argon gas of 15 mL/min, at aheating temperature of 265° C., and for 16 hours. After the purificationby sublimation, 2.8 g of a light yellow glassy solid of an objectivesubstance was obtained at a collection rate of 81%.

The HOMO level and the LUMO level of4-naphthyl-4′,4′-diphenyltriphenylamine (abbreviation: BBAβNB) wereobtained through a cyclic voltammetry (CV) measurement. A calculationmethod is shown below.

An electrochemical analyzer (ALS model 600A or 600C, manufactured by BASInc.) was used as a measurement apparatus. As for a solution used forthe CV measurement, dehydrated dimethylformamide (DMF, product ofSigma-Aldrich Inc., 99.8%, catalog No. 22705-6) was used as a solvent,and tetra-n-butylammonium perchlorate (n-Bu4NClO₄, product of TokyoChemical Industry Co., Ltd., catalog No. T0836), which was a supportingelectrolyte, was dissolved in the solvent such that the concentration oftetra-n-butylammonium perchlorate was 100 mmol/L. Further, the object tobe measured was also dissolved in the solvent such that theconcentration thereof was 2 mmol/L. A platinum electrode (PTE platinumelectrode, manufactured by BAS Inc.) was used as a working electrode,another platinum electrode (Pt counter electrode for VC-3 (5 cm),manufactured by BAS Inc.) was used as an auxiliary electrode, and anAg/Ag electrode (RE7 reference electrode for nonaqueous solvent,manufactured by BAS Inc.) was used as a reference electrode. Note thatthe measurement was performed at room temperature (20° C. to 25° C.). Inaddition, the scan speed at the CV measurement was set to 0.1 V/sec, andan oxidation potential Ea[V] and a reduction potential Ec[V] withrespect to the reference electrode were measured. Note that Earepresents an intermediate potential of an oxidation-reduction wave, andEc represents an intermediate potential of a reduction-oxidation wave.Here, the potential energy of the reference electrode used in thisexample with respect to the vacuum level is found to be −4.94 [eV], andthus, the HOMO level and the LUMO level can be obtained from thefollowing formula: HOMO level [eV]=−4.94−Ea and LUMO level[eV]=−4.94−Ec. Furthermore, the CV measurement was repeated 100 times,and the oxidation-reduction wave at the hundredth cycle and theoxidation-reduction wave at the first cycle were compared with eachother to examine the electric stability of the compound.

As a result, the HOMO level of BBAPNB was found to be −5.47 eV. Incontrast, the LUMO level was found to be −2.28 eV. When theoxidation-reduction wave was repeatedly measured, in the Ea measurement,the peak intensity of the oxidation-reduction wave after the hundredthcycle was maintained to be 83% of that of the oxidation-reduction waveat the first cycle, and in the Ec measurement, the peak intensity of theoxidation-reduction wave after the hundredth cycle was maintained to be92% of that of the oxidation—reduction wave at the first cycle; thus,resistance to oxidation and reduction of BBAPNB was found to beextremely high.

Further, differential scanning calorimetry (DSC measurement) of BBAβNBwas performed by PyrislDSC manufactured by PerkinElmer, Inc. In thedifferential scanning calorimetry, after the temperature was raised from−10° C. to 300° C. at a temperature increase rate of 40° C./min, thetemperature was held for a minute and then cooled to −10° C. at atemperature reduction rate of 40° C./min. This operation was repeatedtwice successively. It was found from the DSC measurement result of asecond cycle that the glass transition point of BBAβNB is 81° C. It wasfound from the result of the first cycle that the melting point ofBBAβNB is 241° C.

The thermogravimetry-differential thermal analysis (TG-DTA) of BBAβNBwas performed. The measurement was conducted by using a high vacuumdifferential type differential thermal balance (TG/DTA 2410SA,manufactured by Bruker AXS K.K.). The measurement was performed underatmospheric pressure at a temperature rising rate of 10° C./min under anitrogen stream (a flow rate of 200 mL/min). In thethermogravimetry-differential thermal analysis, the temperature(decomposition temperature) at which the weight obtaind bythermogravimetry was reduced by 5% of the weight at the beginning of themeasurement was found to be 412° C., which shows that BBAβNB was asubstance with high heat resistance.

Reference Example 3

In this reference example, a synthesis method of3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation:βNP2PC) used for the light-emitting element 3 and the light-emittingelement 4 described above is described. A structural formula of βNP2PCis shown below.

Synthesis of 3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carbazole(abbreviation: βNP2PC)

Into a 200 mL three-neck flask were put 1.9 g (4.8 mmol) of3,6-dibromo-9-penyl-9H-carbazole, 2.4 g (9.7 mol) of4-(2-naphthyl)phenylboronic acid, 0.12 g (0.40 mmol) oftri(ortho-tolyl)phosphine, and 2.7 g (19 mmol) of potassium carbonate.The air in the flask was replaced with nitrogen, and then 40 mL oftoluene, 10 mL of ethanol, and 10 mL of water were added to the mixture.This mixture was degassed by being stirred while the pressure wasreduced. After the degassing, 22 mg (0.10 mmol) of palladium(II) acetatewas added to this mixture. This mixture was stirred at 80° C. for 4hours under a nitrogen stream, so that a solid was precipitated. Theprecipitated solid was collected by suction filtration. The collectedsolid was dissolved in approximately 750 mL of hot toluene, and thissolution was suction-filtered through Celite, alumina, and Florisil togive a filtrate. The resulting filtrate was concentrated to give asolid. The solid was washed with toluene to give 2.6 g of a white powderof the objective substance in a yield of 99%. The synthesis scheme ofthis reaction is shown below.

By a train sublimation method, 2.6 g of the obtained white powder waspurified. In the purification by sublimation, the white powder washeated at 350° C. under a pressure of 3.0 Pa with a flow rate of argongas of 5.0 mL/min. After the purification by sublimation, 2.0 g of awhite solid was obtained at a collection rate of 77%.

The obtained substance was measured by ¹H NMR. The measurement result isdescribed below.

¹H NMR (CDCl₃, 300 MHz): δ=7.47-7.55 (m, 7H), 7.65 (s, 2H), 7.67 (d,J=2.4 Hz, 2H), 7.76 (dd, J₁=8.4 Hz, J2=1.8 Hz, 2H), 7.75-7.97 (m, 16H),8.14 (d, J=1.8 Hz, 2H), 8.51 (d, J=1.5 Hz, 2H)

FIGS. 41A and 41B show the ¹H-NMR charts. Note that FIG. 41B is a chartwhere the range of from 7.20 ppm to 8.60 ppm in FIG. 41A is enlarged.

The thermogravimetry-differential thermal analysis (TG-DTA) of βNP2PCwas performed. The measurement was conducted by using a high vacuumdifferential type differential thermal balance (TG/DTA 2410SA,manufactured by Bruker AXS K.K.). The measurement was carried out undera nitrogen stream (a flow rate of 200 mL/min) and a normal pressure at atemperature rising rate of 10° C./min. The relationship between weightand temperature (thermogravimetry) shows that the 5% weight losstemperature of βNP2PC is higher than or equal to 500° C., which isindicative of high heat resistance of βNP2PC.

This application is based on Japanese Patent Application serial no.2015-157575 filed with Japan Patent Office on Aug. 7, 2015, the entirecontents of which are hereby incorporated by reference.

What is claimed is:
 1. A light-emitting element comprising: a firstelectrode; a second electrode; a hole-transport layer between the firstelectrode and the second electrode; and a light-emitting layercomprising a phosphorescent substance, wherein the hole-transport layerincludes an organic compound represented by general formula (G1),A¹-B-A²  (G1) wherein in the general formula (G1), A¹ and A² separatelyrepresent a group including a benzonaphthofuranylamine skeleton, and Brepresents a group including a fluorene skeleton.
 2. A light-emittingdevice comprising: the light-emitting element according to claim 1; anda transistor or a substrate.
 3. An electronic device comprising: thelight-emitting device according to claim 2; and a sensor, an operationbutton, a speaker, or a microphone.
 4. A lighting device comprising: thelight-emitting device according to claim 2; and a housing.
 5. Thelight-emitting element according to claim 1, wherein the organiccompound is represented by any one of general formulae (B-1) to (B-10),

wherein in the general formulae (B-1) to (B-10), R¹ to R¹⁰, R³⁰ to R³³,R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³separately represent any one of hydrogen, a substituted or unsubstitutedalkyl group having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 6 carbon atoms, a substituted orunsubstituted aromatic hydrocarbon group having 6 to 13 carbon atoms, asubstituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, acyano group, halogen, and a substituted or unsubstituted haloalkyl grouphaving 1 to 6 carbon atoms, wherein at least two of R³ to R¹⁰, R³⁰ toR³³, R⁴⁰ to R⁴³, R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ ineach of the general formulae (B-1) to (B-10) are groups selected fromgeneral formulae (A-1) to (A-8) whose bonding positions are α,

wherein in the general formulae (A-1) to (A-8), R¹¹ to R¹⁸, R²⁰ to R²⁷,R⁶⁰ to R⁶⁷, and R¹⁰⁰ to R¹¹⁵ separately represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 6 carbonatoms, a substituted or unsubstituted aromatic hydrocarbon group having6 to 13 carbon atoms, a substituted or unsubstituted alkoxy group having1 to 6 carbon atoms, a cyano group, halogen, and a substituted orunsubstituted haloalkyl group having 1 to 6 carbon atoms, and whereinR¹⁹ represents a substituted or unsubstituted aromatic hydrocarbon grouphaving 6 to 13 carbon atoms.
 6. The light-emitting element according toclaim 5, wherein the at least two of R³ to R¹⁰, R³⁰ to R³³, R⁴⁰ to R⁴³,R⁵⁰ to R⁵³, R⁷⁰ to R⁷³, R⁸⁰ to R⁸³, and R⁹⁰ to R⁹³ in each of thegeneral formulae (B-1) to (B-10) are groups represented by the generalformula (A-3),


7. The light-emitting element according to claim 6, wherein the organiccompound is represented by the general formula (B-1) or (B-4).
 8. Thelight-emitting element according to claim 7, wherein the organiccompound is represented by general formula (G2),


9. The light-emitting element according to claim 7, wherein the organiccompound is represented by general formula (G3),


10. The light-emitting element according to claim 1, wherein thephosphorescent substance has an emission peak at 440 nm to 520 nm. 11.The light-emitting element according to claim 1, wherein thephosphorescent substance has an emission peak at 500 nm to 600 nm. 12.The light-emitting element according to claim 1, wherein thephosphorescent substance has an emission peak at 600 nm to 700 nm.